Contains reports on four research projects

Brown, S. C.

Coyle, J. E.

Keefe, J. B.

O'Brien, F. J.

Rosebury, F.

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XIX. SHOP NOTESA. IMPROVEMENTS ON A PUNCHED CARD SELECTOR FRAMEHand-sorted punched card systems are commonly used for filing and cross-indexingliterature reference material. However, the use of such a system is worthwhile onlyif the speed and ease of finding the desired material are greater than the similar timespent in preparing duplicate cards under an alphabetical subject-and-author system offiling. For some time the microwave gas discharge group has been using the McBeeCompany "Keysort" cards for its literature file, and has made a number of improve-ments on the standard available equipment for card sorting which increases both thespeed and ease of use.If a file does not include more than a few hundred cards, sorting with a hand needleis perfectly satisfactory. For larger numbers of cards, a standard frame selector isavailable which has the advantages of sorting more cards at once than can be done con-veniently with a hand needle and of requiring no physical effort in sorting. The disad-vantage of the frame selector is that it is difficult to agitate the cards sufficiently toinsure complete separation of the wanted cards. To overcome this trouble, we mountedthe selector on shock mounts and vibrated it mechanically. The vibration was causedby an unbalanced flywheel powered by a 1/20 horsepower electric motor firmly attachedsomewhat off-center to the rear base of the selector.Our literature file is arranged for direct coding of subject material and numericalcoding of authorship. Since the file is almost always searched by subject, single-pinselection is common. Using a mechanical selector, single-pin selection in the positionsnear the center of the card works very well, but within about ten holes of either end ofthe card the rotation of the card about the selector pin tends to jam the cards against thetop of the frame and to reduce the ease with which the punched cards will fall out. Toimprove this feature, we have built a card support that prevents the rotation of the cardswhile they are being vibrated. This support is illustrated in Fig. XIX-1 in the positionin which the cards are put onto the selector frame. The support may be put onto theframe on either end of the cards, dictated by the position of the selector pin about whichthe card might rotate. The support is of Dural and is attached by compressing the wingears of the spring clips and sliding the support along the guide rods, mounted on the topof the selector frame, until the support meets a stop block. When the wing ears arereleased, spring clips engage slots in the guide rods which locate the exact position ofthe support.A view of the modified selector frame is shown in the photograph in the selectingposition (Fig. XIX-2). To eliminate the noise which the frame makes when mechanicallyvibrated, several steps had to be taken. All metal washers throughout the frame werereplaced by rubber ones. The sorting tray was held down by the springs, shown inFig. XIX-2, when the direct coding along the long edge of the card was being used. When-96-Fig. XIX-1Detail of the card support.Fig. XIX-2Improvements on a punched card selector frame.-97-(XIX. SHOP NOTES)the coding at the end of the cards was used, the springs were disconnected, and thesorting tray was folded up against the back of the frame, held by the clips, whichare also shown. The switch on the motor vibrator can be seen in Fig. XIX-2, thoughthe motor itself is on the back of the frame.S. C. Brown, J. E. CoyleB. VACUUM-TIGHT GLAND FOR PUSH-ROD AND ROTATINGSHAFT APPLICATIONSThe basis of the gland is a Lunkenheimer No. 1324 compression tee, 3/8 inch tubingsize. The body A (Fig. XIX-3) is reamed through to take the rod B, a piece of 3/8 inchstainless steel rod, which has been polished. The crosspin E is a piece of 1/8 inchround stainless steel, force-fit, that serves to tighten or loosen the nut D which is insidePUMPATMOSPHEREVACUUMFig. XIX-3Vacuum-tight gland.-98-t(XIX. SHOP NOTES)the evacuated chamber. The three packings C are made from 5/8 inch Teflon rod,turned, as shown, to the shape to fit the seats in the tee body originally intended for thecopper compression sleeves that are not used. The Teflon pieces need not be made withhigh precision because when the nuts are tightened the Teflon will cold-flow into place.Note that the nut inside the vacuum D has been modified: a slot has been milled in it totake the crosspin B, and also some of the hexagon body has been turned off to allowspace for mounting the tee in the vacuum wall, and to allow space for tightening. Thetee is hard-soldered into the vessel wall at F. The cross handle at B is a loose fit toallow for assembling; it may be fixed in place by means of a setscrew G.A mixture of Octoil with some molybdenum disulphide sparingly applied to thefriction surfaces made operation of the gland adequately smooth both for turning andsliding motions.F. J. O'Brien, F. RoseburyC. VACUUM COLD TRAPThe body of the trap is a cylinder of seamless stainless steel tubing 4 inches indiameter; the 2-inch-diameter inlet and outlet tubes are Kovar, which allows a glass-to-metal seal. The partition, shown in Fig. XIX-4, is a piece of stainless steel sheet,cut to fit snugly inside the diameter of the cylinder and extending to within approximately1. 5 inches of the bottom. This sheet is first tack-welded to the top disc. The edges and top are tinnedwith soft solder before assembling into the cylinder theinside walls of which are also tinned along the areas ofcontact. The inlet and outlet tubes and the top andbottom discs are welded or brazed in place, and uponapplying heat along the outside of the cylinder at theplaces where the partition is in contact a seal iseffected by the soft solder.A feature of this trap is the cold partition which isessentially at the same temperature as the cylinderI ~walls because of the metallic contact, thus providing. . a large area of cooling surface in a trap of relativelysmall size. The trap was designed for use with a one-gallon dewar flask.The inlet and outlet tubes may, of course, beFig. XIX-4 attached at almost any position and not limited to theVacuum cold trap. 1800 position shown in Fig. XIX-4.F. Rosebury-99-(XIX. SHOP NOTES)D. ELECTRIC VACUUM SEALThe seal was designed to eliminate gasketing material. The detailed unit(Fig. XIX-5) is approximately 25 inches in diameter. The reservoir was made fromrectangular steel tubing with one narrow side removed. The heating element is a 3500-watt, 230-volt General Electric 4A-422 immersion unit, 0. 333 inch in diameter.TINSEDRFig. XIX-5Diagram shows skirt immersed in molten tin bath.To make a seal, the reservoir on the lower half is heated until the tin or solder ismolten. The upper half with the skirt is lowered into the reservoir and allowed to cool.Any section that does not wet satisfactorily can be readily touched up. After a few sealsare made and opened, the skirt becomes completely tinned and the seal goes togethereasily.J. B. Keefe-100-

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