US1080421A - Telemeter. - Google Patents

Description

V. COLZI & F. BARDELLI.

TELBMBTBR.

APPLICATION FILED MAR. 3. 1910.

l ,1080,42 1 Patented Dec. 2, 1913.

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N 1fy R 1%: PIV/IP /P V. COLZI @c F. BARDELLI.

TBLBMETER.

APPLICATION FILED MAILS, 1910A Patented Dec. 2, 1913.

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V. COLZI & F. BARDELLI.

TELBMBTER.

APPLIOATION FILED Mmm. 1010.

Patented Dec. 2, 1913.

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STATES PATENT OFFICE.

VIRGILIO COLZI AND FELICE BARDELLI, 0F TURIN, ITALY.

TELEMETER.

To all 'whom t may concern:

Be it known that we, VmeILio Comi and FELICE BARDELLI, both subjects of the King of Italy, residing at 1S Via Roma, Turin, Italy, have invented certain new and useful Improvements in Telemeters; and we do hereby declare the following to be a full, clear, and eXact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to letters or figures of reference marked thereon, which form a part of this specification.

The present invention relates to telemeters having a fixed base and instantly giving the distance of a distant object sighted, by a single observation, and has for its object improved moditications of the telemeter described in our Patent No. 1,058,556, dated April 8, 1913.

The main features of the present improvement relate to the telescopic system, the measuring device, the rectifying device, and the means fo-r supporting or suspending the instrument, as will hereinafter be more fully described and particularly pointed out in the claims.

In the accompanying drawings, showing by way of example, one form of our improved telemeter, and in which like parts are similarly designatetl-Idigure l shows the field of the eye piece or ocular of the telemeter. Fig. 2 is a perspective view of the central system of erecting prisms and the associated prisms of the rectifying system. Figs. S and 3a are diagrams showing the action of a rotating prism on a luminous ray. F 4l and 5 show prisms forming the optical part of a measuring device having, respectively, two and three prisms and made and operating in accordance with the presentinvention. Fig'. 6 is a diagrammatical elevation of the telescopic and rectifying systems. Fig. 7 is a horizontal longitudinal section through the telemeter on line 7 7 of Fig. 1Q. Fig. 8 is an elevation of one of the prisms of the objectives. Figs. t) and l0 show the field of the eye piece of the rectifying system in two positions. Fig. 11 shows the telemeter in rear elevation with its supporting tube in vertical longitudinal section. Fig. 12 is a front elevation. Fig. 13 is a section on line 13"-13 of Fig. 11. Fig. 14: is a cross-section showing the Specification of Letters Patent.`

Application filed March 3, 1910.

Patented Dec. 2, j 913.

Serial No. 547,137.

relative position of the oculars and the separating prism.

It has been found in practice that the upper and lower portions of the image, 1 and 2, Fig. 1, are simultaneously visible in a diminished or paler condition, as indicated at 3 and 4l, notwithstanding the use of the thin opaque plate or sector 5 in the horizontal plane of the division between the upper and lower halves of the images at the eye piece. Such phantom image, or double representation, is confusing to unskilled observers, and it is desirable that the two portions 1 and 2 only of the image be visible in the eye piece. It also causes the images at ordinary dis tances to be less distinct. IVe have overcome this objection and annoyance to unskilled observers by cutting the prism of the erecting system, I4 Q, in the plane of reflection 7 o-f the opaque sector 5, vf. c., in a plane parallel to the emergent face of the prism, and cementing the parts together again. The

plane 7 constitutes therefore a sort of prolongation of the sector 5 in the direction of its reflection and prevents the oblique luminous rays from near the `junction of the two prisms, S, 9, from passing beyond this plane. The images 1 and 2, Fig. 1, are rendered clear, and those less sharp, or phantom, images, 3 and 4l, are avoided.

The measuring device, which is the most important part of the present invention, consists in its essential form of two prisms whose refracting edges are adjacent and parallel, so that when in closed position they act substantially as a single glass having parallel or nearly parallel faces. In the present invention these two prisms are mounted to rotate in a plane perpendicular to their parallel refracting edges and thereby open with respect to one anotliel angularly or like a fan. This measuring device is founded on the following principle: A luminous ray It, Fig. 3, passing through the prism l is deviated or retracted to l", being bent toward the base of the prism. Then the prism I) is moved to the right or left of a plane perpendicular to its base and through its ret'racting edge, in this instance the vertical plane, the ray R becomes refracted to a greater extent, that is, through a wider angle. In the position of the prism 7), the ray It. is deviated to r, and in the position p, to r1. The deviation of the ray It increases not only with the increase in the angle of rotation of the prism P, but to a greater extent, so that equal successive angles of rotation of the prism produce increasing deviation, each greater than the preceding one. It is upon this fact and action that our novel measuring device is based. One prism alone, however, is not suiicient to constitute a proper measuring device, not only by reason of coloring the images, (chromatic aberrations) but chiefly on account of the deformation of the images, the deformation being so great as to destroy their details. This deformation may be prevented by assembling two identical prisms and causing them to rotate to equal extents in opposite directions, thereby compensating the deformation, and to this end the measuring device will assume the form shown in Fig. 4. Ttk is still necessary, or desirable, to obviate the coloring of the images, due to dispersion. rThis may be done in two ways, either by using two acliromatic prisms, or by inserting a third stationary prism which is termed the neutralizer between two prisms P. This third, stationary. prism may have an angle twice that of the movable prisms, or may be of flint or crown glass. Such an arrangement is shown in F ig. 5 which is the preferred form, and the system of three prisms will be equal to a glass having parallel faces, when the laterally movable prisms are' in their initial or closed position.

The construction may be made general by adopting two movable prisms having different angles, in which case the stationary neutralizing prism must have an angle equal to the sum of the angles of the two movable prisms.

lf the three prisms are all of the same kind of glass, dispersion will be produced when the two movable prisms have reached their useful maximum movement or rotation, which may be 400 or thereabout, for each prism. In this case it will be necessary either to make all the prisms achromatic, or make the neutralizer of flint or crown glass with an ang e capable of correcting, slightly in excess, the dispersing power of the two movable prisms when in their initial or closed position, and not quite capable of fully correcting the defect when the two movable prisms have been moved to their maximum extent.

lt will be understood that in order to always obtain perfect images the movable prisms should rotate by slightly different amounts, and this difference must be determined by experiment for each instrument. This difference in the angle or speed of rotation of one of the movable prisms with respect to the other, will be, of course, less when the two prisms have a different angle of refraction, as in the general case above referred to, and it will be an inverse function of said difference between the angles of refraction. 1t will also be necessary to determine it by experiment for each di'erence of angular amplitude and in each instrument. Tn this measuring device the luminous ray is deviated by a slight movement of the movable prisms, and as already remarked, is deviated by an amount constantly increasing with' each unit increase of opening of the prisms or rotation from their initial position. Tn known measuring devices the luminous ray, under the same conditions, has always an equal deviation. Consequently in this device in order to obtain a uniform rate of deviation of the ray for equal angular movements of the prisms, it will be necessary to eifect a rapid movement of rotation of the prisms at the beginning of their movement from their initial positions, and a slower one toward the end of their movement. ln other words, the speed of rotation varies inversely as the angle between the two prisms, while in known devices the angle of rotation of the two prisms must be constant, or nearly so.

The closed measuring device is mounted for viewing objects at the greatest distance and its rotation is the greater the nearer the object observed, the maximum distance of the object corresponding to a minimum rotation of the prisms, and the minimum distance to the maximum rotation. Tt is also known that the displacement of the image of the object observed greatly increases as the object is approached. From this fact combined with the manner of operating the measuring device above described it results that :-a. ln known measuring devices the movement of the prisms and consequently the displacement of the scales fixed thereto, is relatively small for a distant object approaching, for instance from 6,000 to 5,000 meters and considerably greater for anobject moving by the same amount but closer, for instance approaching from 3,000 to- 2,000 meters. o. In the measuring device made in accordance with our present invention, the rotation of the prisms and consequently the displacement of the measuring scales is somewhat increased for distant objects and considerably reduced for closer ones. Therefore the scales in the known measuring devices must be graduated with lines drawn very close to one another for distant objects, and with lines wider apart the nearer the object. ln the present measuring device the scales are graduated uniformly or practically so, owing to the compensation for the displacement of the image and for the rotation of the prisms, which rota-tion must decrease as the object is approached. Moreover, as the decrease in the spaces between thelines of the scales for close objects in the known forms is much greater than the inadjusted, then, after the displacement of the prisms of the measuring device, in order to cause the two parts of the image of the viewed object to coincide or register in the field of the eye piece of the telemeter, the field of the eye piece of the rectifying device is observed, and. it will be found that the lower scale has been displaced due to the rotation of the prisms of the measuring device. rIhe displacement of this scale read by means of the upper scale or vernier, the position ot' which has not changed, is in direct proportion to the displacement of the prisms of the measuring device, and consequently to the distance of the viewed object; the extent of this displacement checks the reading effected by the measuring device.

The prisms 10 and 11 are illumined through the slots 29 and 30 provided in the casing 31 of the telemeter, Figs. 7 and 12. rllhese openings may be circular, as shown in dotted lines in Fig. 12, and may be provided with lenses in order to concentrate a greater quantity of light on the prisms 10 and 11.

The mounting of the instrument inside a protecting tube 31 is such as to render the instrument insensible to or unaffected by either the elastic or the permanent deformations of the tube, and especially those changes due to temperature variations. This is attained by causing the whole telemeter to rest on four points, placed in pairs, and the points of a pair diametrically opposite and located on two vertical diameters so distanced from the center of the telemeter that its weight is equally distributed on both sides ot these supports.`

rlhe points of support are on four steel balls 32 located in steel seats 33 mounted in or connected to the intermediate rings 34 of the telemeter body. These balls also seat in plates 35 secured by screws 3G, Fig. 13, to the outside of the tube 31, Figs. 11, 12 and 13. The radii of curvature of the seats 33 is slightly greater than the radius of the balls 32, so that the latter contact with the seats at one point only. rtherefore, whatever the dilation of the tube 31 it will not produce any deformation of the telemeter body. Even torsion or fleXure (especially the bending in a horizontal plane so harmful to optical mechanism) of the tube 31 is not transmitted to the telemeter body, owing to said suspension at the :tour points with the play between the balls and their seats.

lV@ claim 1. ln a telemeter, the combination with an opaque sector, of a totally refiecting prism composed of two portions cemented together, the plane of cementation lying in the plane of reflection of said sector in said. prism.

2. ln a telemeter, the combination wit. an opaque sector of a totally reflecting prism composed of two portions cemented to- 7gether, said sector positioned proximate the upper half of the emergent tace of the prism, and the plane of cement-ation lying in the plane of reflection of said sector in said prism.

3. ln a telemeter, the combination with an opaque sector, of a totally reflecting rightangular prism composed of two portions cemented together in a plane parallel its hypotenuse and the sector positioned opposite the end of said plane perpendicular to the hypotenuse.

4f. ln a telemeter, the combination with a thin opaque sector, of a totally reflecting right-angular prism composed of two portions cemented together in a plane parallel to its hypotenuse, said sector positioned perpendicular to and substantially bisecting one half or the hypotenuse or emergent face of the prism and opposite one end of the plane of cementation.

5. In a telemeter, the combination with a two part cemented totally reflecting prism, of an opaque sector cooperating in conjunction with the plane of cementation of said prism to separate the images distinctly into two portions and avoid the formation of phantom images.

6. ln a telemeter, a measuring device comprising a pair of prisms perpendicular to the optical axis of the telemeter and oppositely rotatable in a plane perpendicular to their refracting edges.

7. ln a telemeter, a measuring device comprising a pair of prisms in and perpendicular to the optical axis of the telemeter and oppositely rotatable in planes perpendicular to their refr-acting edges at different angular speeds.

8. In a telemeter, a measuring instrument comprising a pair of prisms in and perpendicular to the optical axis of the telemeter and oppositely rotatable in planes perpendicular to their refracting edges, and means to chromatically correct said prisms.

9. ln a telemeter, a measuring instrument comprising a pair of prisms in and perpendicular to the optical axis of the telemeter and oppositely rotatable in planes perpendicular to their refracting edges, said prisms being movable at different angular speeds and means to chrolnatically correct said prisms.

10. ln a t-elemeter, a measuring instrument comprising two prisms in and perpendicular to the optical axis of' the telemeter and a third prism located between them whose refracting angle is substantially equal to the sum of the refracting angles ofthe other two prisms.

11. In a telemeter, a measuring instrument comprising two equal parallel prisms in and perpendicular to theoptical axis of the telemeter and rotatable in planes perpendicular to their refracting edges, and a third inverted prism located between them whose reti-acting angle is equal to the sum of the refracting angles of the parallel prisms.

12. In a telemeter, a measuring device comprising two equal right triangle prisms in and perpendicular to an optical axis ot the telemeter, and a third inverted prism located between them whose retracting angle is double the refracting angle oil one otl the parallel prisms said parallel prisms being cppositely rotatable in planes perpendicular to their refracting edges.

13. In a telemeter, a measuring device comprising two equal right triangle prisms in and perpendicular to the optical axis o't' the telemeter, and a third inverted prism located between them whose reti-acting angle is double the ref'racting angle of one otl the parallel prisms said parallel prisms being oppositely rotatable in planes perpendicular to their reti-acting edges at different anglilar speeds.

l-t. In a telemeter, a measuring device comjjirising two equal right triangle prisms in and jiierpendicular to an optical axis of the telemeter, and a third inverted prism located between them whose refracting angle is double the refracting angle ot one oit the parallel prisms said parallel prisms being' oppositely rotatable in planes perpendicular to their retracting edges and whose outer :faces are parallel to one another' when in Zero position.

15. In a telemeter, a measuring device comprising a pair of prisms in and perpendicular to the optical axis ot the telemeter oppositely rotatable in planes perpendicular' to their relracting edges at ditlierent angular speeds, and a glass having plane parallel faces in and perpendicular to the optical axis pivoted to swing at an angle to said axis to correct for errors arisingin de'f'ormation of the instrument.

1G. In a telemeler, a measuring instrument comprising` a pair of prisms in and perpendicular to the optical axis of' the telemeter and oppositely rotatable in planes perpendicular to their refracting edges, said. prisms movable at different angular' speeds and means to chromatically correct said prisms and a glass having plane parallel faces in and perpendicular to the optical axis pivoted to swing at an angle to said axis to correct for errors arising in deformation of the instrument.

17. In a telemeter, the combination with the erecting prisms thereof; ot' a measuring device to one side of said prisms, comprising parallel equal, right angle prisms in and perpendicular to the optical axis of the telemeter oppositely movable at different angular speeds in planes perpendicular to their retracting edges and a stationary inverted prism whose ref'racting angle is equal to the sum of the refracting angles oit' the movable prisms, the outer faces of which said movable prisms are parallel when in zero )osition and a glass having plane parallel .taces to the other side of said erecting prisms in and perpendicular to the optical axis of the telemeter and mounted to move at angles to said axis.

18. The combination with a telemeter having objective prisms, each having a reflector on a portion of its face, of an eye piece, a pair oif crossed reflecting prisms reflecting into the same, a prism on each side o said crossed prisms, having an index on one ot its faces, means to illumine the latter prisms to direct the light to the said reflectors which in turn reflect the light to the crossed prisms.

19. The combinatitm with a telemeter having two objective prisms, one having a retlector on the upper half ot' its forward laci and the other on the lower hallE of its forward face; of an eye piece, a pair of crossed juxtaposed prislns reflecting directly into the same, a prism on each side of said crossed prisms, less in height than one of them, an index on the emergent face of each of said latter prisms directed toward said reflectors and means to sejiarately illumine the latter prisms.

Q0. The combination with a telemeter having two oppositely situated objective prisms, ot' a reflector on the upper halt of the ilicident face of one and the lower half ot' the incident tace of the other slight-ly inclined to said face, an eye piece, a pair ot super-posed juxtaposed crossed prisms reflecting directly into said eye piece, a prism opposite each of the crossed prisms of less height than said crossed prisms and located respectively above and below the optical axis ot' the telemeter, oneI of said prisms having` engraved on its emergent face a scale and on the einer'- gent face oi the other, a vernier, means to separately illumine the latter prisms whereby they will direct light. to the reflectors which in turn will reflect to the crossed prisms that again reflect to the eye piece where the scale and Vernier are viewed in proper relation to one another.

21. The combination with a telemeter having light receiving prisms, each having a reflector on a portion ot its face, of an eye piece, a pair of crossed reflecting prisms reflecting into the same, a side prism on each side ott said crossed prisms, having an index on one ot its faces, means to illumine the latter prisms and direct the light reflected 'from said side prisms to the said reflectors which in turn reflect the light to the crossed prisms, and means to deflect the rays -from one of the reflectors into a parallel p'ath before reaching the crossed prisms.

22. rIhe combination with a telemeter having light receiving prisms, each having a reflector on a portion ot' its f'aee, ot an eye piece, a pair of crossed reflecting prisms refleeting into the same, a prism o-n each side of said crossed prisms, having an index on one of its faces, means to illumine the latter prisms to direct the light to the said reflectors Which in turn reflect the light to the crossed prisms, and optical means to compensate for deformations of the telemeter.

23. The combination with a telemeter having two oppositely situated objective prisms, of a reflector on the upper half of the incident face of one and the lower half of the incident face of the other slightly inclined to said face, an eye piece, a pair of superposed juxtaposed crossed prisms refiecting directly into said eye piece, a prism opposite each of the crossed prisms of less height than said crossed prisms and located respectively above and below the optical axis of the telemeter, one of said prisms having engraved on its emergent face a scale and on the emergent face of the other, a Vernier, means to separately illumine the latter prisms Whereby they will direct light to the reflectors which in turn will reflect to the crossed prisms that again reect to the eye piece Where the scale and Vernier are viewed in proper relation to one another, and a rotatable glass having plane parallel faces in the path of the rays reflected by one of the reflectors.

In testimony that We claim the foregoing as our invention, We have signed our names in presence of two subscribing Witnesses.

VIRGILO COLZI. FELICE BARDELLI. Witnesses:

PIERO GIANoLis, EUGENIO G. B. CosnTTA Fonzro.

Copies of this patent may be obtained for ve cents each, by addressing 'che Commissioner of Patents, Washington, lD. C.

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