US2408316A

US2408316A - Adjustment fixture

Info

Publication number: US2408316A
Authority: US
Publication date: 1946-09-24
Anticipated expiration: 1963-09-24

Description

Patented Sept. 24, 1946 UNITED STATES PATENTKOFFICE ADJUSTMENT FIXTURE Vincent G. Jarman, Watchung, N. J assignor to .Western Electric Company, Incorporated, New York, N. Y., a corporation of New-York Application March 23, 1943, Serial N0. 480,169

4 Claims.

This invention relates to an adjustment fixture and more particularly to a device for holding an article to be operated on in predetermined relation to means for illuminating and inspecting the article.

There are many instances in various arts where an article composed of a plurality of components needs to have minor adjustments of its component elements relatively to each other made after assembly of the article before the article is satisfactorily usable for its intended purpose. Thus, certain vacuum tubes for use in the electrical arts have a double, concentric grid, i. e. a pair of flattened helices of wire of. the same pitch, of which one is within the other and both are mechanically supported on a common base by means of separate pairs of posts. For some uses, it is impor tant that each half turn of the wire of one helix lie accurately parallel to the corresponding half turn of the other helix and in a plane perpendicular to the common plane of the four posts of the two helices.

An object of the present invention is to provide a device or adjustment fixture to hold an article in predetermined relation to a predetermined line of sight and to a means of illumination, and having means to change the position of the article in predetermined fashion with respect to the line of sight.

With the above and other objects in view, the invention may be embodied in a device or fixture having means to determine a line of sight, a support to receive and hold an article in the line of sight, means to illuminate the face of the article facing the line of sight, means to adjustably traverse the support perpendicularly to the line of sight, and means to rotate the support about an axis perpendicular to the line of sight.

Other objects and features of the invention will appear from the following detailed description of one embodiment thereof taken in connection with the accompanying drawing in which the same reference numerals are applied to identical parts in the several figures, and in which Fig. l is a view in perspective of a double grid adjustment fixture constructed in accoradnce with the invention;

Fig. 2 is adetached, enlarged, centraL-vertical section through the lens and first screen;

Fig. 3 is a detached, enlarged, section through the grid support traversing means and rotating means, transverse to the line of sight;

Fig. 4 is a section through the showing of Fig. 3 and at right angles thereto;

(Cl. 24,8-r-124) 2 Fig. 5 is a front elevation of a double grid to be held in the fixture; v

Fig. 6 is a section on the line 6-6 of Fig. 5; Fig. 7 is a plan view of the leftend of the showingof Fig. 3 with the grid assembly removed, and Fig. 8 is a front elevation of the showing of Fig. 7.

The apparatus herein disclosed as an illustrative embodiment of the invention, is a fixture for holding and inspecting a double concentric grid intended to be used in vacuum tubes, while the turns of the helices of the grid are being manually adjusted to mutual parallelism. To make the nature, purpose and scope of the invention as illustrated in this particular embodiment more easily apprehended, the grid assembly, which is no part of the invention, will be described first so far as relevant to the invention. 1

The grid assembly, for which the device of the invention is primarily designed, is shown by itself, in one specific form only, in Figs. 5- and 6. It comprises a pair of identically similar bases 18 and l I of insulating material, preferably ceramic, in which are mounted, in a central plane, longitudinal of the unit as a whole and transverse to the bases Ill and l I, four metal members 1 2, which will be the plate of the vacuum tube, and two pairs of metal rod grid supports I ,4, l5 and I5, ll respectively. The two rods of each pair are on oppositesides of the plate members l2 and coplanar with these, the pair [4, It being also outside of the pair l6, ill. The plate members 12 terminate, hold together, and space apart the bases ill and II. The grid supports l4, l5, l6 and H pass through and extend beyond the outer faces of the bases. The plate members are electrically interconnected by means not visible in the figures and also to terminals l3 mounted on the under face of the base Ill. Elastic, laminar, contact fins l8 are mounted on the bottom ends of the rods [4, l5, I6 and H.

The rod-shaped grid supports I l, l5, l6 and I1 are each provided on their outer sides with suitably spaced and located notches I9, 20, 2! and 22 respectively, to hold and support the consecutive coils or turns of two flat helices .25 and 25 of wire. The supports are so held inthe bases and the notches in the support are so spaced and located that to each notch 2| corresponds a notch I9 at the same distance from the base l0, and to each notch 22 similarly corresponds a notch 26, except for the two uppermost and one lowermost notches 2| and 2-2 for which there are no correspondent notches. e

The notches are further so located and spaced that a wire 23 wound in the notches l9 and 2D and a wire 24 wound in the notches 2i and 22 in the manner shown, form the two

helices

25 and 26 respectively, whose respective half turns are to run parallel each to each in planes perpendicular to the plane of the plate members I 2. The article each half turn of one or the other helix is adjusted to run parallel to its correspondent in the other helix and with the common plane of the two at right angles to the axial plane of the assembly. This is the purpose and function of the device or fixture shown in Figs. 1 to 4 inclusive. This fixture comprises a main base 33, either heavy enough in itself to give stability to the whole or to besecured or clamped on a bench or table. Upon this is mounted a tiltably adjustable, platelike base 3|. An upstanding, transverse wall member 32 is rigidly secured on the base 3 1. Near the upper edge of the wall 32, two parallel

tubular supports

33, 33 are rigidly mounted in the wall, extending therethrough at right angles thereto.

Support rods

34, 34 are slidably adjustable in the tubes 33 and may be clamped in adjusted position by means of

clamp screws

35, 35. A depending laminar screen or optical diaphragm 3B is rigidly supported on the forward ends of the tubes 33, and is formed with a transverse slot 31. On the forward ends of the rods 34 is mounted a depending, transverse housing 38 in which is a laminar screen or optical diaphragm 39 formed to fit over the front surface of a magnifying lens 40 also held in the housing 38. The screen 39 has a transverse slot 4|. An eye shade 42 may be mounted on the forward side of the housing 38 if desired. The front faces of the wall 32, screen 35 and screen 39 are preferably made matt black by being suitably painted or Otherwise.

' Between the wall 32 and the screen 35, a grid assembly support block 43 is mounted on a rack 44 to be pivotable about an axis in the line of reciprocation of the rack. The rack is reciproball 53 acting on corresponding indentations 5i in the integral pivot formed on the rack, to maintain the block 43 yieldingly in either of two positions 180 apart. The block 43 is formed on its upper side with a groove or slot 52 to act as clearance space for the parts of a grid assembly which project below the assembly base It when the assembly is placed on the block 43 in the position indicated in the first four figures.

To positively locate the grid assembly in an accurately predetermined position on the block 43, there is provided a positioning member 53 mounted on the block 43 across one'end of the slot 52. The thickness of the member 53 is the same as that of the grid assembly base ID. The member 53 is formed with locating means

such asfingers

54, 54 to fit into and engage corresponding means on the base H], e. g. the

recesses

55, 55, and so to locate the base It! on the block 43 in an accurately predetermined relative position. To hold the grid assembly removably in this

position clip springs

56, 56 are provided to frictionally engage the base [0.

Along one up and down edge of the screen and behind the screen is positioned an elongated light source, e. g. a fluorescent lamp 5'! in tubular form, fed with electric current from any convenient source, not shown. Such a light source will illuminate the front side of a grid assembly, mounted on the block 43 as indicated in Fig. 1, in a substantially shadowless and glareless manner, as seen through the slot 4|, lens 49, and slot 31, making accurate inspection of the grid wires easy and not tiring to the eyes, since the light falls on the horizontally disposed wires over a considerable angle from well below the line of sight to well above it. Hence, each wire visible in the field of vision is substantially equally illuminated over a portion of its periphery greater than the visible portion. To ensure this, as well as to concentrate attention on the particular pair of wires tobe adjusted, the slots 4| and 31 are so dimensioned that with the forehead against the eye shade 42 and the rack 44 suitably elevated, the particular air of wires in question will lie horizontally and one behind the other across the middle of the elongated narrow horizontal field of view, preferably with a few but only a few of the neighboring pairs above and below also in sight. If the slots be narrow enough to limit the field to a single pair of wires, diffraction disturbances are apt to produce eyestrain, darkening of the field and indistinctness. A convenient basic factor is to select the lens 49 with a focal 49, 49. Means as indicated by the spring pressed length of 6 to 12 inches, preferably about 9 inches, and dimension the rest of the apparatus to correspond. The distance of the lens 40 from a grid assembly on the block 43 is made adjustable at 35, 35, to adjust this to the requirements of different eyes.

Since the grid wires to be adjusted relatively to each other lie in different planes transverse to the optical axis of the device, i. e. at different distances from the eyes, it is practically necessary to have the apparatus arranged for binocular vision as otherwise it would be difficult, or even impossible, for the operator to be visually certain which of two grid wires under simultaneous observation stands in front of the other. Hence is derived the peculiar value of the slotted diaphragms defining the horizontally elongated and vertically limited field of vision.

With the apparatus as shown in Fig. 1 and a grid assembly in place on the block 43 and the block in its lowest position, the front half of the top coil or turn of the outer helix 25 should be at or below the horizontal center line of the field of View. If it is below the center, the half turn is brought up to the center by turning one of the knurled heads 49. The corresponding front half turn of the inner helix 26 should then be invisible over its whole length behind the half turn of the outer helix 25. If it is not, the operator, with a pair of tweezers or other suitable implement, will bend one or the other or both half turns of the pair until this condition exists. A head 49 is then turned to bring the next pair of front half turns to the center of the field and these are corrected if necessary. This is repeated until the whole front side of the assembly has been inspected and corrected if necessary, coil by coil. The block 43 is then rotated, forcingthe spring latch'5fl out, until it catches again 180 away. The rear side of the assembly is then presented for inspection with the bottom pair of corresponding half turns nearly in position in the field of view. The rear turns are preferably inspected from bottom to top in same manner that the front turns were inspected from top to bottom. The operator will not then forget to inspect both sides, knowing that when a piece of work is all the way up, it is only half done.

It will be noted that the apparatus as described combines, as basic components, an optical system comprising the lens 40 and the screens or

optical diaphragms

36 and 39, together with the article support means which is capable of being adjusted to traverse an article thereon across the optical axis of the optical system and also to rotate the support and article, independently of the traversing motion, about ,an axis perpendicular to the optical axis, into two predetermined positions 180 apart in either of which the sup port is yieldingly locked; The number of positions thus provided for, is two in the particular embodiment chosen to illustrate the invention, because the grid assembly to be dealt with has two aspects to be considered. In other instances the article in question might have three or four or even more aspects, in which case a corresponding number of indentations 5| to receive the ball latch 58 would be provided.

The invention has been illustrated as embodied in an apparatus for holding a particular grid assembly in and adjustably moving it across an illuminated, limited field of View to facilitate inspection and adjustment of correlated turns of windings; but the invention is believed not to be so limited. Modifications and variations to adapt it to other types of articles to be examined are believed to be obvious to those skilled in the art on the carrier to be rotatable thereon about the axis of motion thereof with respect to the support base.

2. In an optical device for observing and holding articles to be adjusted and having an optical system for observing an article, a, support base rigidly mounted beside and spaced from the optical axis of the system, a support carrier mounted in the support base to be adjustably traversable therein toward and from the optical axis at right angles thereto, and an article support mounted onthe carrier to be rotatable thereon about the axis of motion thereof with respect to the support base, together with means to yieldingly lock the article support on the carrier in eith'er of two angularly spaced positions thereon.

3. In an optical device for observing and holding articles to be adjusted and having an optical system for observing an article, a support base rigidly mounted beside and spaced from the optical axis of the system, a pinion mounted in the support base, a rack housed in the support base and engaging the pinion to be traversable thereby toward and from the optical axis at right angles thereto, and an article support pivoted on the rack to be rotatable thereon about the axis of motion thereof.

4. In an optical device for observing and holding articles to be adjusted and having an optical system for observing an article, a support base rigidly mounted beside and spaced from the optical axis of the system, a pinion mounted in the support base, a rack housed in the support base and engaging the pinion to be traversable thereby toward and from the optical axis at right angles thereto, and an article support pivoted on the rack to be rotatable thereon about the axis of motion thereof, together with means to yieldingly lock the article support on the carrier in eith'er of two angularly spaced positions thereon.

VINCENT G. JARMAN.