US3692268A

US3692268A - Positioning mechanism

Info

Publication number: US3692268A
Application number: US112200A
Authority: US
Inventors: Gerald J Laughlin
Original assignee: Singer Co
Current assignee: Link Flight Simulation Corp
Priority date: 1971-02-03
Filing date: 1971-02-03
Publication date: 1972-09-19
Anticipated expiration: 1989-09-19

Abstract

The disclosed embodiment of the present invention is a mechanism for positioning the CRT (cathode ray tube) at the object plane of an optical system, thereby permitting focusing of the image projected by the system. A plate for supporting the CRT is provided with a notch in an edge parallel to the direction of travel of the plate. The CRT plate is supported by a mounting surface which contains a row of offset holes in such a position that they align with the notch when the CRT plate is installed thereon. A camming tool having a shaft with an eccentric member mounted thereon and a handle disposed for manual rotation thereof is provided for effecting relative motion between the CRT plate and the mounting surface. The diameter of the eccentric member attached to the shaft of the camming tool is substantially equal to the width of the notch in the edge of the CRT plate, and the diameter of the shaft of the camming tool is substantially equal to the diameter of the holes in the mounting surface. In use, the shaft of the camming tool is inserted into one of the holes in the mounting surface, such that the eccentric member is received within the notch. Rotation of the camming tool imparts a force on the CRT plate which, in turn, displaces the CRT along the optical axis.

Description

United States Patent Laughlin [151 3,692,268 5] Sept. 19, 1972 POSITIONING MECHANISM [72] Inventor: Gerald J. Laughlin, Palo Alto, Calif.

[73] Assignee: The Singer Company, New York,

22 Filed: Feb.3, 1971 211 Appl.No.: 112,200

[52] US. Cl. ..248/346, 248/23, 269/66, 269/321 T [51] Int. Cl. .iFl6m 13/00, HOSk 13/00 [58] Field of Search ..248/346, 23; 108/102, 143; 269/66, 321 A, 321 T, 58, 59

[56] References Cited UNITED STATES PATENTS 406,828 7/1889 Fietsch ..269/32l ME 2,778,235 1/1957 Amonsen ..248/23 X 3,408,924 11/1968 Mueller ..269l321 ME 3,074,177 1/1963 Duroisin ..'...248/23 X Primary Examiner-Chancellor E. Harris Attorney-Francis L. Masselle, William Grobman and Andrew G. Pullos ABSTRACT The disclosed embodiment of the present invention is a mechanism for positioning the CRT (cathode ray tube) at the object plane of an optical system, thereby permitting focusing of the image projected by the system. A plate for supporting the CRT is provided with a notch in an edge parallel to the direction of travel of the plate. The CRT plate is supported by a mounting surface which contains a row of offset holes in such a position that they align with the notch when the CRT plate is installed thereon. A camming tool having a shaft with an eccentric member mounted thereon and a handle disposed for manual rotation thereof is provided for effecting relative motion between the CRT plate and the mounting surface. The diameter of the eccentric member attached to the shaft of the camming tool is substantially equal to the width of the notch in the edge of the CRT plate, and the diameter of the shaft of the camming tool is substantially equal to the diameter of the holes in the mounting surface. In use, the shaft of the camming tool is inserted into one of the holes in the mounting surface, such that the eccentric member is received within the notch. Rotation of the camming tool imparts a force on the CRT plate which, in turn, displaces the CRT along the optical axis.

4 Claims, 3 Drawing Figures PATENTED 19 I973 3.692.268

Fig.3

INVENTOR. Fig 2 GERALD J. LAUGHLIN POSITIONING MECHANISM This invention relates generally to positioning mechanisms and more particularly to a mechanism for positioning, along the optical axis, an image on the face of a CRT disposed in an optical system to thereby focus said image.

In the past, positioning of a CRT for purposes of focusing an image thereon employed an adjusting screw which was operated by a knurled knob. To move a CRT employing an adjusting screw requires many turns of the knurled knob to move only a small distance. This precise positioning mechanism was slow and tedious.

The positioning of a CRT by the use of an adjusting screw and knurled knob can often be substantially inaccessible' for operation. An adjusting screw must operate directly on the element to be positioned, and the knurled knob must be connected directly to the adjusting screw. This requirement usually places the knurled knob in a location difficult for an operator to reach.

The use of an adjusting screw as a positioning mechanism requires careful realignment each time the CRT was removed and replaced. Also, the parts employed in an adjusting screw mechanism were expensive because accurate machining of many small parts was required. Accordingly, it is an object of the present invention to provide a positioning mechanism which offers ease of operation while permitting relatively fine adjustment.

It is another object of the present invention to provide a mechanism which can accurately position a CRT rapidly.

Another object of the present invention is to provide a camming tool with a handle for operation constructed to a length convenient for accessibility.

Still another object of the present invention is to provide a positioning mechanism that requires no critical realignment following removal and replacement of the CRT.

It is still a further object of the present invention to provide a positioning mechanism that is simple and inexpensive to construct. A

A feature of the present invention resides in the provision of a camming surface, formed in the disclosed exemplification of the present invention of a notch in an edge of a plate, and a plurality of holes having a predetermined positional relationship to the camming surface and permit fine, but relatively rapid and easy, adjustment of the plate.

These and other objects, features and advantages of the present invention will be more fully realized and understood in the following detailed description, wherein:

FIG. 1 is a perspective view, partly cut away, showing a positioning mechanism for a CRT constructed in accordance with the principles of the present invention;

FIG. 2 is a partial plan view of the CRT plate and mounting surface particularly showing the slot in the CRT plate and the row of holes in the mounting surface in alignment therewith;

FIG. 3 is a sectional view taken along line 3-3 of FIG. 1 showing the camming tool in alignment with the CRT plate and mounting surface.

With reference to the drawings in detail and in particular to FIG. 1, there is shown a cathode ray tube (CRT) which is mounted in an optical system (not shown) with the longitudinal axis 12 thereof being Still another feature of the present invention resides vantage of permitting relatively fine adjustment between two members, such as a CRT plate and a mounting surface therefor. Furthermore, such fine adjustment can be made using the present invention with relative ease by an operator. This advantage is further enhanced by the relatively short time required to perform the adjustment.

coincident with the optical axis of the optical system. The base plate 14 which is integral with the supporting structure of the optical system forms a mounting surface for the CRT 10 and its associated supporting structure. The CRT 10 is supported along its length by

members

16, 18 and 20, which members extend from and are rigidly secured to a plate 22.

The CRT base plate 22 is mounted on the optics base plate 14 by means of

bolts

24, 26 and 28 which extend through

slots

30, 32 and 34, respectively, in the plate 22 and threadably engage the plate 14. The

elongated slots

30, 32 and 34 permit relative motion between the CRT base plate 22 and the optics plate 14 along the axis 12. v

The position of the CRT base plate 22 with respect to the optics base plate 14 along a direction orthogonal to the axis 12 is accurately maintained by alignment blocks 36 and 38 engaging a edge 40 of the base plate 22 and by an alignment block 42 engaging a edge 44 of the base plate 22. Accordingly, it can be appreciated that the CRT 10 and its associated supporting structure can be positioned along the axis 12 by loosening the

bolts

24, 26 and 28, moving the plate 22 with respect to the optics base plate 14 to the desired position, and tightening the bolts to maintain the desired position. It will be appreciated that any lateral movement will be restrained by the

alignment blocks

36, 38 and 42. The position of the CRT 10 can be refined for accurate focusing within the optical system by employing the positioning mechanism of the present invention.

A notch 46 is provided at one edge of the CRT base plate 22, with

opposite sides

48 and 50 of the notch forming camming surfaces which are orthogonal to the axis 12. A plurality of holes 52 are provided in the optics base plate 14 which align with the slot 46. A plan view of the alignment of the holes 52 with respect to the notch 46 is better shown in FIG. 2.

The holes 52 are arranged in two rows, with each row extending in the direction of the desired path of displacement of the plate 52 with respect to the plate 14. The centers of the holes in one row are equal distance between adjacent pairs of holes in the next row. As will be appreciated from the description of FIG. 3, the maximum distance between the centers of the holes is a critical dimension.

As shown in FIG. 3, a camming tool, generally designated with the reference numeral 54 is provided for effecting relative motion between the CRT plate 22 and the optics base plate 14 and includes a shaft 56 for engaging individual holes of the plurality of holes 52 and an eccentric member 58 mounted on the shaft 52 with a handle 60 extending therefrom for manual rotation thereof. The eccentric member is circular in structure to prevent any backlash while positioning the CRT plate. ln-operation, the camming tool shaft 56 is inserted into an individual hole 52a which is aligned with the notch 46 as shown in the sectional view of FIG. 3. With the camming tool 54 in the position shown in FIG. 3, rotation of the handle 60 imparts a force on the camming surface 50 by virtue of the rotation of the eccentric member 58. This force, in turn, causes a displacement of the CRT base plate 22 to the right as shown in the drawing.

If it is desired to continue movement of the CRT plate 22 in a direction to the right, as shown in FIG. 3, after the above described displacement is effected, the shaft 56 is inserted into a subsequent hole and the tool 54 is again rotated. However, if such displacement is not effected, the shaft 56 can be inserted into a hole 52c and subsequent rotation of the handle 60 would move the CRT plate 22 to the left as shown in the drawing. The maximum distance the CRT plate 22 can travel with one insertion of the camming tool is equal to twice the distance the eccentric member 58 is offset from the shaft 56. The distance the CRT plate 22 is displaced, or twice the offset distance, is defined as the differential of the eccentric member 58.

The individual adjacentholes in the plurality of holes 52 are offset one from the other, and are disposed along an axis parallel to the optical axis a distance equal to or less than the differential of the eccentric member 58. More particularly, the holes 52 in a preferred embodiment are disposed a distance substantially less than the differential of the eccentric member to provide ease of inserting the tool 54 into respective member mounted thereon for engaging said camming surface, said means including individual means for engaging said shaft and restraining movement thereof in one direction opposed to the direction of the force on said camming surface exerted by said camming tool, adjacent ones ofsaid individual means being positioned relative to one another a distance at least equal to the differential of said eccentric member.

2. A mechanism as defined in claim 1 wherein said notch is located in an edge parallel to the direction of travel of said plate.

3. A mechanism as definedin claim 2 wherein the width of said notch is substantially equal to the diameter of said ecce tric rn ber f r e a in th reof. 4. A mechanism as defined in claim 1 for focusing an image on the face of a CRT' disposed in an optical system, wherein said CRT is mounted on said plate, and the individual means being formed of a plurality of holes in said mounting surface for engaging said shaft.

. a camming tool having shaft with an eccentric

Claims

1. A positioning apparatus comprising: a. a plate having a notch in one edge forming a camming surface; b. means forming a surface for mounting said plate for slidable movement thereon in a direction orthogonal to that of said camming surface; and c. a camming tool having shaft with an eccentric member mounted thereon for engaging said camming surface, said means including individual means for engaging said shaft and restraining movement thereof in one direction opposed to the direction of the force on said camming surface exerted by said camming tool, adjacent ones of said individual means being positioned relative to one another a distance at least equal to the differential of said eccentric member.

3. A mechanism as defined in claim 2 wherein the width of said notch is substantially equal to the diameter of said eccentric member for engaging thereof.

4. A mechanism as defined in claim 1 for focusing an image on the face of a CRT disposed in an optical system, wherein said CRT is mounted on said plate, and the individual means being formed of a plurality of holes in said mounting surface for engaging said shaft.