US2386394A - Binocular - Google Patents

Description

`Oct; 9, i945. J. A. GRIER BINOCULARS Filed7 Jan. 7, 1942 2 sheets-sheet 1 lle 77 mvl-:NTOR

J. A. GRIER Oct 9, 1945.

BINOCULARS 2 Sheets-Sheet 2 I Filed Jan. '7, 1942 INVENTOR Patented Oct. 9, 1945 'John Ali-red Grier, "Yonkers, 'N.v

Y., assigner "to 'ftionio'f NewYork Application January '7, 1942,.'Serial No. 425,816

' 17e-claims.

Y.'Ihisfinvention `relates =to. improvements in'binoculars `and has `for an object 'theprovision -Yof instruments the lcasings 4or barrels 'of"which1are each L4composite l structures formed of @parts which when fitted and lsecured 4together inherently .hold the various axes .and plane/surfaces `.therein Vin proper :relation 'with each fother.

In :the structures I'herein 'shown and described, thepar-ts :forming rny'compos'ite `barrels are made entirely of parts which are punched andeform'ed, and/oridraw'n. .Likewise all of 'the parts of Ithe eyelens .mountings Iand the objective 'mountin'gs are punched or y'drawn with the exception of L-the eye =cap .'(lwhich vispreferably made of rubberor other plastic). In i.this specification the lterm .sta-mped shall lbe taker'l to mean-#made fin a die, by punching, b'lanking, forming, 'or fdrawing, and/,or combinations thereof; sand the term fstampings shall be taken to lmean-:stamped parts. The degree of accuracy can largely be insured by ythe lcare and exactitude exercised .in the making Iof the dies.

Another 4object 'ofthe-invention :is the .provision of a binocular barrel in which the .prism shelf is formed rof a plurality Tolf flat stampings, fthe middle :one .of lwh-ichiorms Ythe 'shelfper rse, and others on each side thereof, membering up 1therewith and conjointly fonming depressions for faccurately locating the Porro prisms with each other and with the optical axes of the eyepieoes and the objectives.

A further object of the invention is the forming of a binocular barrel l"of ahollow outer rshell, a prism shelf assembly .in `said shell,V Iand upper and lower spacer members telescopin'g in said shell for holding said shelf a predetermined distance from at least one end-of said shell and for rigidly maintaining saidshelf ltherein With the plane surfaces thereof at right angles 'to the axis of said shell. It is obvious that if the ends Iof the shell are square with the axis, the surfaces of the prism shelf will. be parallel to said ends.

Yet another object of the invention is the pro-V vision of a binocular barrel formed of, a hollow outer shell, a prism shelf assembly in said shellV in a plane intermediate the end planes of said' shell, a plate at one endadapted to support the eyepiece assembly, a plate at the other end adapted to support the objective mounting, spacer members Within said shell for holding the prism shelf and said plates in parallel spaced relation to each other, and means for securingv them in this relation.

The stack comprising the plates, the prism shelf and vthe spacer members therebetween iS by i-weldinig,

'preferably as tall -asthe length `of 'the 'hollow outer shell, isofthat after assembly the outerlsur`- faces offrrsaid ffplates are ilush with lthe ends of said outer `shell. The 'Sparts may be *secured together solder-ing, or 'by utilizingscrews vas will hereinafter be described. A modification contemplates Pma'king the lshell longer :than 'the stack 'and spinning or "curling 'the 'ends of the shell :over the 'top fand bottom plates.

Anotherlobjeet-ef `the Linventlenis .the .provision of fextensions 'of' fthe top and bottom plates Lto extend 4outwardly and form hinge varms `for 'the binocular. 1` Y A further object `of the @invention is `'the provision 1in #the 1evapiece istruc'tu'repf fa binocular of .novel means of sealing between the A'statioi'l'ary andthe fmovable fpart's fto Kireviit `the 'ingress *of dust 'or moisture.

.Another-'object i's'rthe proyisonfof a `noi/e1 double eccentric arrangement to facilitate 'the collimatirlg fo'f the binoculars 'after assembly.

Another object of the invention fis the prvison ef :a binnen-leraren substantially 'no inechine work is cene ranu which fis readily aceptable terapia mass production.

other objects and avantag'es for the invention will be apparent to those skilled in the art upon perusal of the follovif-ir'l'g description of th'e inl/'eh- 'I'l. n 1

Rererring te the `'cl-r'eiwin'gs 'are `given by Way lof *example to illustrate in illnr Of bract-ieing the invention; f h

VIiguife 1' anlfatibr'r, -altly in `Alsec'tio'll, showing 'the structure o'f the composite barrel and the relation ef t1-ie parteteeefeh other;

Figure 12 is a plan view of the binocular o'f Figure 1, the lett heli er Figure i bei-ng 'teken along th line 2L-2 f Figli-re 1, adfthe right half being 'a plan view ofthe barrel lwith the ocular andthe tfop cover 'plate removed; Y n

Figure '3 'is a sectional elevation of the left barrel as seen in the direction on Figure 2^; Figure 4 is a se'cl'jional elevation, enlaigd, showing a `'c'lo'llble feceei'i't'rfic adjustment for the objective with respect tothe opticalv 'axis of the instrument;

assembly Figures is e Asectional' elevation ef the neuter Figure 6 4,le e iragmehteryyvew' showingthe strap loop formed of the rubber coating on the mediate the' ends of the shell. A spacing member 22 telescopes the shell and forms therein a ledge contacting the upper face of the prism shelf? L around the edges thereof.

In contact with the upper edges of the spacing member 22 is a top plate 2?.` which carries ya threaded hole, to be presently described'forV sup-1 porting the ocular. The upperfsurf'ace of this top plate is flush with the upper edges of the shell 20.

A second spacing member 24 telescopes in the shell from the lower end thereof and the upper edges of this member contact and form ak ledge for the lower'face of the prismshelf 2|. In contact with the bottom edges of the spacing member 24 is a vbottom plate 25; the lower face of which is Vflush with lthe bottom' vedges of .the shell 26."

In other words, the height of the pile, comprised of the bottom plate 25, the spacing member 24, the prism shelf assembly 2|, the spacing member 22, andthe top plate 23, is equal to the height of the shell 26. These parts are positioned in the'shell and secured therein in any suitable manner, such as, by soldering or welding; however, because certain advantages (to be presently described) are obtained, I prefer to secure these parts together by screws, as may be seen 'in Figures 1 and 2, and designated by the numeral 26.

These screws preferably have flat heads countersunk in the topplate 23 and engage threaded holes, not shown, formed'in the bottom plate'25. These screws pass through clearance holes 21 formed inthe prism shelf 2|.

In Figure 2, the left barrel is out along the line 2 2 of Figure l, and the upper spacing member 22 is omitted so that the entire -upper surface ofthe prism shelf assembly2| can' be plainly seen. Y Y

The-prism shelf 2| is actually formed of three stampings. The upper stamping 28 has an elon'- gated hole 29 formed therein exactly the shape of the base-of the prism and forming an exact fit with the prism, for example the prism 33. A round` hole 3|)A isalso formed inthe plate 23 to permit light to pass through to the ocular, as will hereinafter be described. The plate 28 lalso carries a plurality of holes 3| which 'clear the screws,

to be described, for retaining the prisms.

The middle plate 32 is in contact with the lower face of the plate 28 and the upper surface of the plate 32 forms, with the hole 29, a bottomed depression or socketf for the prism. This middle plate has holes 34, 35 iand 36 formed therein through which the light passes as will be described hereinafter. This plate carries `'tapped holes 31 Afor 4securing the prisms to the shelf.

The lower plate or stamping 38 islike the stamping28 except that'it is reversed, an elongatedhole 39 in contact with the lower surface ofthe middle plate 32, forms a depression into which the lower prism 40 fits, and a hole 4| therein is aligned with the hole 34.V

4The prism .clamp springs 42 resliently and firmly hold the prisms in the depressions 29 and 39,.-and consist of portions spanning the apex of the prism and extending down on each side of the prism to points where they bend outwardly and form ears adjacent to the prism shelf.

-gitudinally thereof and prevent it from moving out of its' socket endwise.

"V''In' the left barrel Figure 2, the upper telescopic spacing member 22, and the prisms have been l5" 'omitted sothat a clear view of the upper side of theprismshelf assembly may be had.

The top plate 23 has a struck in portion 41 which is threaded to accommodate the stationary. tube 46 of the ocular 48. 'Ihis ocular will be described in detail hereinafter in connection with Figure 5. The top plate 23 also has an arm 49 which extends outwardly through a notch in the outer shell 2U to cooperate with other parts to form a hinge connection between the barrels. These features are illustrated in Figure 3 and will hereinafter be described in detail. Portions of the top plate are cut away for lightening its weight, and at the same time permitting the prism to be inserted and mounted on the prism shelf. 1

The bottom plate 25 has a struck in portion 56 which is threaded to accommodate the shank 5| of the objective assembly 52. One form 0f objective assembly is shown in Figure l and a modied form is shownin Figure 4. Both of these will be hereinafter described in detail. An arm 53, preferably formed integral with the plate 25 extends outwardly to be included in the hinge joint between the barrels as will be hereinafter described.

shoulder formed in the tube 46 bears down on the surface immediately about said clearance hole, and in addition to this `the top cover'plate may also be secured to the top plate by means of screws, one of which is shown at 55 in Figures 1 and 2.

A bottom cover plate 56 covers the bottom plate 25 and has a rim overlapping the bottom edges of the outer shell 20, and has a clearance hole therein to clear the shank 5| of the objective assembly. A shoulder adjacent to said shank bears on an annulus immediately about this clearance hole. The cover plate is also secured to the bottom plate by meansv 0f screws 51.

The Vparts of the Vright barrel are identical with the parts in the left |barrel above described, except that they are rights and lefts. The frights parts in the right barrel are indicated by numerals like those of the lefts in the left barrel with the addition of the letter a, For

The portion of the shells 20 and 20a'l between the flanges of the upper and lower cover plates Y carries a rubber coating 58 which may be molded von and in some instances the loop 5B may also be formed integral with the rubber of said coating, see Figures l and 6.V The rubber coating may feather out at the top and the bottom of the shell 26, as indicated at 60 in Figure 6, and when engaged, by the flanges of the cover plates, a

water and dust tight seal .is .eiected therewith.- ;Referrng 110W to Figure .3 it'will be noted that this iS an elevation, vpartly .in the Section f the left fbarrel taken along the line 3-:3 .of Figure Iihelarni ,49 has .a portion 6.| of reduced thickness, thereby forming .a shoulder 62. I Likewise the arm153 has a portion 6 3 of reduced thickness and a shoulder 04. The shoulders 62 and .6 4 are arcuate in form, the centers of the arcs being on the `centerline or the hinge.

The arm ,49a of the right Abarrel has va PQrtion cut away to match the portion :6| of the arm 4 9 and form therewith a flush knuckle joint, andy likewise the lower arm 53a of the right barrel has a portion cut a-way to match the portion 63 of the arm 5.3 and form therewith a second flush knuckle joint. These knuckle 4joints have aligned holes therethrough into which is fitted a shaft .9 5.

Bearing against Athe lower surface of the upper knuckle joint is a cupped washer '56, and bearing the washer `69 fits into a depression 1 3 lin the arm 4 9, thereby maintaining the washer in fixed relation to the arm .49, and a screw 'i4 is threaded into the upper end of the yShaft 65- A cupped washer 'I5 bears .against the lower surface of the lower knuckle joint, and a screw 16 extending therethrough is threaded into the lower end of the shaft 65. Within the hollows of the cupped washers I place washers formed .of sheet Neoprene and, since the cupped wash- EIS are Spr-inail. I am able to adjust the screws 1 4 and 'I0 to obtain just the right friction in the knuckle joints.

The objective mounting ,52 is shown elllrged in the sectional elevation Figure 44. -The shank r5| of the .outer shell 'Il is 4screwed into the threaded hole in the boss on the bottom plate Z5, It will be noted that the outer shell 1l is stepped to house the lens cell and other parts .comprise ing double eccentrics to facilitate collimatina. Within the shell 1 7 is a stepped eccentric ring 1.8, the upper portion of which embraces a flange 78, and the lower portion of which embraces .the body of the lens `cell .80, which is also eccentric. Within the lens cell is the objective lens set 8| which is retained therein by a threaded ring 8 2. A clamping ring 83 is within the lower step of the eccentric ring l0 and threaded into the shell .11,- The ring 83 beers against the .eccentric ring, and it in turn presses the flange 7,9 into contact with the annular shoulder 89 formed in the shell A ring is screwed into the lower end of the lens Cell .80- It may be formed 0f elasticY audits, inner surface may be tapered as shown `and may have diffraction rings formed therein,

The lower end of the lens cell 80 and the lower edge of the eccentric ring 19 may have slots or longitudinal holes formed therein to be engaged by Va tool so that they may be moved circumferentially in the process of collimating the instrument.' shell has an opening formed therein, through which light may pass to the objective lens, and forms a cover barring the user from access to the adjustments.

A closure ring 86, threaded intol the In :Eis-ure `details of kszon..sirzurztior1 of the eyepiece are The .stationary tube 4:6 has its lower @mi stepped and the portion 89 threadedly `@Defects @a threaded hole formed in the hess 41 of the top plate 23. The shoulder `81 resultjingfrom the step may be `seen bearing on the the upper end .of 9| to permit light to pass from the lens 92 to the eye, The outer surface of the socket 9| is threaded for purposes to be presently described.

Within the tubular member at the top there.- of is a cupped disc 94 having a hole 9.5 there- A through. The cupmatches the socket formed in 9| and they cooperate to properly align and mount the eyelens 9 2.v

The tubular member has a helical slot 916 formed in the wall thereof, and this slot is engaged by a radial stud 9 8 which is carried by an arcuate tongue `9'! formed in the wall Vof the stationary tube `46, so thatas the tubular member 99 is rotated it vwill (at the same time) be moved longitudinally in the stationary tube 46.

The upper end of a spacing tube 99 telescoping in the tubular member 9,0 engages the rim 94a of the `cupped disc 91|, and the lower end of said spacing tube is engaged by the held lens |00. A threaded ring I0| is screwed into the lower end of the tubular member 90, maintaining the lens |00, .the tube 99, and the cupped disc in the relation shown.

The outer barrel |02 has its upper end turned in radially-to form a ledge 03, and the hole therein snugly fits the outer surface of the socket 9| The Wall of the barrel |02 is deformed outwardly to form a raised'ring |04, and inside the barrel an annular hollow is formed for containing a packing ring |05. formed of any suitable material, but at'present I use an artificial rubber such as Neoprene, because it effects a water tight seal with the outer wall of the stationary tube 46, does not chale the metal of said wall and is not affected by climatic condition or by oils, etc.

A second raised ring |96 is formed in the barrel |02 spaced apart from the ring |05, and both have their outer surfaces knurled.

The skirt |01 of the barrel is tapered and carries a, diopter scale.

A locking ring |08 threadedly` engages the threads on 9| and is screwed down against the flange I 03 for clamping it to maintain the d iopter setting.

A non-metallic eyecap |09 threadedly engages the threads on 9| Aand bears against the upper surface of the flange |03, and at the same time encloses the locking ring |00. A series 0f gl'OOves ||0 is formed in the conical opening in the eyec ap. The interior of the portion 89 is also threaded to accommodate the reticle cell 88. This cell has a portion forming a shoulder ||I which abuts the lower end of the portion 89 and .aCcurately positons the reticle ||2 with respect to the focal point. In practice the reticle is use d only in connection with the left eyepiece.

In the modification shown in Figures 7 and 8, the parts forming the composite barrel are similar to those described above, and the method lof supporting the prism shelf is also similar- The The packing ring may be outer shell 2tlg is left sufficiently longer than the sums of the parts mounted therein to permit the excess length to be spun over to permanently secure the partsrtogether as will presently be described.

'Ihe shell 20g may have straight sides, in which the top plate 23g and the bottom plate 25g may be the same size. If it were not for the fact that the eyepiece boss 41g in the top plate is smaller than the objective boss tlg in the bottom plate, these plates could be identical.

The prism shelf consists of three members 28g, 32g, and 38g which are identical with the members 218, 32, and 38 except for the outside outline. This shelf is positioned in the shell 20g, and between it and the top plate 23g, is a spacer member 22g telescoping in the shell 20g and accurately spacing and paralleling the prism shelf and the top plate.

Between the prism shelf and the bottom plate 25g is a second spacing member 24g accurately spacing and paralleling said shelf and said bot= tom plate.

The outer shell has straight sides normally terminating along the dotted lines andvnotched to accommodate the hinge arms 49g and 53g. After the prism shelf, the spacing members and the top and bottom plates are assembled in the shell 20g as described, the structure may be clamped together and the ends 20c and 20d of the shell 20g are curled over, in any suitable manner, thereby forming beads ||3 and I |4. A barrel structure constructed in. this manner is light, exceedingly rigid, and inseparable.

A further modification is shown in Figure 9, wherein the outer shell 20 has a composite prism shelf therein, comprised of three members, as is the case in the forms previously described, designated by the numerals |28, |32, and |38. Anupper spacer member |22 contacts the upper surface of the prism shelf and extends upwardly to the top of the outer shell. The upper edge of the spacer member is flush with the top end .of the `Shell |20.

A lower spacer member |24 has its upper end in contact with the under side of the prism shelf and its lower end is flush with the bottom of the outer shell |20. In assembling the barrel, the parts are placed together in the relation described, then clamped with suitable means for holding the mentioned ends in parallelism. The parts may then be soldered, silver soldered, or welded (spot) to maintain them in 'such relation.

The upper cover |54 carries the eyepiece barrel |46, and has its outer end |43 extended to form an upper hinge arm. By bending the sides of the end |49 downwardly (as shownai-J |48) to form a channel, sufficient strength may be obtained for extremely light duty binoculars.

The lower cover |2'5 carries the objective |52, and has its outer end |53 extended to form a lower hinge arm, the sides being bent to form a channel for strengthening said lower arm. The prisms |133 and |40 are shown positioned on the prism shelf and suitable means, such as for example, the spring 42 may be provided for retaining said prisms thereon.

The objective assembly shown in Figure 1 1s similar to the one shown in Figure 4 with the exception that it does not have the eccentric member 18, therefore the arrangement shown in Figure 4 is preferable.

Although the parts forming the composite barrel structures have been describedas secured together in various ways, I prefer to secure them together with screws 26 in the manner shown in Figures 1, 2, and 3, because; after the parts are made, Athe barrels 2U may be sent; to the vulcanizers to have the coating 58 bonded to the outer surface thereof and the strap loops 59 formed thereon. While this is being done, another department may blacken the surfaces of the other parts, including the screws 26 and 43 and the prism springs 42, by lacquering and/ or plating.

After all the parts are finally finished, they may be assembled, collimated, packed and shipped at a rate many times as rapidly as has been heretofore known in the art. r

It will be understood that the forms of the invention herein described are given by way of example and are therefore not limitative, as many changes may be made in the arrangements shown and described without departing from the spirit of the invention as set forth in the appended claims.

I claim:

1. In a prism telescope, a barrel including an outer shell, a prism shelf positioned within said shell, an upper spacer member positioned within said shell with its lower end in contact with a portion of the upper surface of said shelf and having its upper end adjacent to and parallel with the upper end of said shell, a lower spacer member positioned within said shell with its upper end in contact with a portion of the lower surface of said shelf and having its lowerV end adjacent to and parallel with the lower end of said shell, `and means forv securing said shell, said spacer members, and said shelf together with said sheif substantially parallel with the ends of said shell.

2. In a binocular, an outer shell, separate means telescoped into each end of and forming opposed ledges within said shell, and a prism shelf positioned between and contacted by said ledges.

3. In a prism binocular, an outer shell, a prism shelf positioned within said shell, a spacer member telescoped into said shell and extending from said shelf to the top of said shell, a second spacer member telescoped into said shell and extending from said shelf to the bottom of said shell, 'and means for securing said shell, said members, and said shelf together to form a composite structure.

4. In a binocular, an outer shell, separate hollow members telescoped into and forming opposed ledges and opposite ledges within said shell, a prism shelf positioned between and contacted by said opposed ledges, a lens support in one end of said shell in contact with one of said opposite ledges, and a, second lens support in the opposite end of said shell and in contact with the other of said opposite ledges, said prism shelf and said lens supports being maintained in parallelism by said separate means, t

5. In a binocular, an outer shell, separate means telescoped into and forming opposed ledges and opposite ledges within said shell, a prism shelf positioned in said shell between and in contact with said opposed ledges, a top plate engaged by one end of said shell and in contact with one of said opposite ledges, said top plate being adapted to carry an eyelens assembly and having a hinge arm projecting therefrom, a bottom yplate engaged by the opposite end of said -shell and in contact with the other of said oppolsaid top plate and said shelf for maintaining said relation, a bott-om plate in said shell lin spaced parallel relationto the oppositefface of saidfshelf,

a second spacer member telescoped in said shell between said bottom plate and said shelf for maintaining said relation, means for securing said shelf, said spacers, said plates Aand said shell together to form a composite structure, and hinge arms extending laterally from said plates to points outside said shell.

'7. In a binocular, an outer shell having aligned notches formed in each end thereof, a prism support in said shell, a top plate positioned within one end of said shell and having aI hinge arm extending therefrom through one of said notches, means within said shell and in cooperative relationship with both said support and said top plate for maintaining the outer surface of said top plate substantially parallel to and in definite space relation to said prism support, and a bottom plate positioned within the opposite end of said shell and having a hinge arm extending through the other of said notches, and a second means within said shell and in cooperative relationship with both said support and said bottom plate for maintaining the outer surface of said bottom plate substantially parallel lto and in delinite space relation to said prism support.

8. In a binocular, a top plate forming a support for an ocular lens assembly, a bottom plate forming a support for an objective lens assembly, a prism shelf, a spacer member between said shelf and said top plate for spacing them apart in parallel relation to each other, a second spacer member between said shelf and said bottom plate for spacing them apart in parallel relation to each other, and means for rigidly maintaining all said parts in the relations set forth.

9. In a binocular, an outer shell, a top plate fitting in said shell and forming a support for an ocular, said plate having a, hinge arm extending laterally therefrom, a bottom plate also fitting in said shell and forming a support for an objective and having a hinge arm extending therefrom in alignment with said first hinge arm, a prism shelf, a casing, a pair of members, each having its ends parallel, one of said members being positioned between said tcp plate and said shelf and the other being positioned between said bottom plate and said shelf for maintaining said shelf between and in spaced parallel relation with said plates.

10. In a binocular, a top plate forming a support for an ocular lens assembly, a bottom plate forming a support for an objective lens assembly, a prism shelf, a spacer member between said shelf and said top plate for spacing them apart in parallel spaced relation to each other, a second spacer member between said shelf and said bottom plate for spacing them apart in parallel relation to each other, and means extending through said top plate said shelf and said bottom plate for securing them together to form a rigid composite structure.

11. In a binocular, a top plate forming a support for an ocular, a bottom plate forming a support for an objective, a prism shelf, a spacer member between and in contact with said shelf and said top plate for spacing them apart in parallel relation to each other, a second spacer forma composite structure. Y

12. In a prism telescope, a stationary tube se- `vcured thereto, an eyepiece draw `'tube reciprocally carried in said stationary tube, means partially Al'carried on said stationary tube and partially carried in said draw tube to cause the latter to move longitudinally in said stationary tube as said draw tube is rotated, a diopter scale tube settably mounted on said draw tube and embracing said stationary tube, said diopter scale tube being provided with an inwardly facing annular depression, a synthetic rubber sealing ring in said depression contacting said stationary tube and maintaining a fluid tight seal between the latter and said diopter scale tube.

13. In a prism telescope, a stationary tube secured thereto, a draw tube reciprocably carried in said stationary tube, a curved slot formed in the Wall of said draw tube, an arcuate arm formed integral with said stationary tube, a stud carried by said armI and engaged by said slot, a lens socket formed at one end of said draw tube, a cupped member cooperatingwith said socket for holding an eyelens therein, a field lens in said draw tube spaced apart from said eyelens, a spacing tube within said draw tube covering said arcuate slot and maintaining a definite spacing between said field lens and said eyelens, an outer tube secured to said draw tube and embracing said stationary tube, and an articial rubber ring carried in said outer tube and forming a sealed joint with said stationary tube for sealing the interior of said telescope against the ingress of extraneous matter.

14. In a prism binocular, an outer shell, a prism shelf positioned within said shell, a separate spacer member telescoped into said shell and in contact with and extending from said shelf to a point adjacent to the top of said shell, a second separate spacer member telescoped into said shell from the opposite end thereof and in contact with and extending from said shelf to a point adjacent to the bottom of said shell, the top of said shell being spun over the upper end of said first spacer member, and the bottom of said shell being spun over the lower end of said second spacer member for securing said members and said shelf rigidly within said shell.

15. A binocular according .to claim 6 in which the upper end 0f the outer shell extends slightly beyond said top plate, and in which the bottom end of the outer shell extends slightly below the bottom of said bottom plate; and in which the means for securing said members together, to form a composite structure, constitutes the spunover ends of said outer shell onto said t-op plate and said bottom plate.

16. In a prism telescope, a, barrel including an outer shell, a at prism shelf telescoped into said shell, a separate member shorter than said shell, and telescoped into said shell from one end thereof to present a ledge in c ontact with one face of said prism shelf, a second member also shorter than said shell .telescoped into the other end thereof and presenting a ledge in contact with said-prism shelf, the lengths of said members, plus the thickness of said shelf, being no longer than the height of said shell.

17. In a prism telescope, a stationary tube secured thereto, a draw tube reciprocably carried in said stationary tube, a curved slot formed in memberV between and in contact Vwith said shelf and said bottom plate for spacing `thenn apart in parallel relation to each othen-and a'casing embracing-said parts-and engaging' said platesto the Wall of said draw tube; studaneansl carried *Y on said stationary tube and engaged by said-slot, a lens socket yformed at Q nevend ofrsaid draw f tube, a cupped )member cooperating. with vsaid socket for holding an eyelens therein,-a^e1d lens in said draw tube spaced apart from said eyelens, an iirnperforate spacing tube within said draw tube for both covering said arcuate slot and maintaining a predetermined spacing between said eid lens and said` eyelens, an outertube secured to said draw tube and embracing said stationary tube, said outer tubev having an inwardly facing annular -grooveformedr therein, Aand a ring of rubberlike material carried in said

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