US3335497A - Scribing instruments - Google Patents

Description

C. H. STEIN ET AL Aug. 15, 1967 SGRIBING INSTRUMENTS 2 SheetsSheet -1 Original Filed April 20, 1961 wwx mHu v 5 M WMK m CW ATTORNEY Aug. 15, 1967 C. H. STEIN ET AL SCRIBING INSTRUMENTS Sheet I 2 Sheets Original Filed April 20. 1961 ZOZF INVENTORA' 07/1815) H. 575M! ATTORNEY WILL/AM lffiA USI 3,335,497 SCRIBING INSTRUMENTS Charles H. Stein, Westwood, and William Krause,

Secaucus, N.J., assignors to Keutfel & Esser Company, Hoboken, N.J., a corporation of New Jersey Application Mar. 1, 1965, Ser. No. 443,743, now Patent No. 3,271,862, which is a division of application Ser. No. 104,482, Apr. 20, 1961, now Patent No. 3,197,871, dated Aug. 3, 1965. Divided and this application Mar. 7, 1966, Ser. No. 553,590

8 Claims. (Cl. 3327) The present application is a division of application Ser. No. 443,743 filed Mar. 1, 1965 now Patent No. 3,271,862, which was a division of application of SN. 104,482 filed Apr. 20, 1961, which issued as Patent 3,197,871 on Aug. 3, 1965.

The present invention relates to instruments for making master templates for cartography circuit cards and the like where accurate duplications are essential for accurate registry in maps and to obtain constant electrical characteristics in duplicate circuit cards including constant resistance of conductors and constant capacitance between adjacent conductors in each completed circuit card.

Heretofore scribing and cutting instruments of many different designs which usually had a single scribing or cutting edge have been'used but the lines and cuts have been coarse and irregular and the edges of the outlined areas have not been parallel and even with a photographic reduction step in the process the reproductions particularly in circuit cards have had objectionable variations in the sizes of the conductors with resulting inaccuracies in the circuits. Also, the previous method of production of a circuit card master with the heretofore known instruments involved many delays.

The present application is a continuation-in-part of our application S.N. 817,852 filed June 3, 1959, now abandoned.

Another object is to provide compass scribing and cutting instruments which trace the pattern for circuit cards.

Other and further objects will be apparent as the description proceeds and upon reference to the accompanying drawings, wherein:

FIGURE 1 is a perspective of a scribing type drop center compass with two radially adjustable arms formed of sets of leaf springs supporting adjustable clamps at their outer end with scribing devices and their supports in the clamps for simultaneously scribing two circles or arcs of different radii.

FIGURE 2 is a side elevation of the double arm drop center compass scribing device of FIGURE 1 as seen from the side having the fixed scribing element.

FIGURE 3 is a top plan view of the drop center compass double arm scribing device of FIGS. 1 and 2.

FIGURE 4 is a section taken substantially on line 44 of FIGURE 1 showing the fixed scribing point in its cartridge with the cartridge in the cartridge support held in the clamp at the end of one radially adjustable arm of one pair of leaf springs.

FIGURE 5 is a section taken substantially on line 5-5 of FIGURE 1 showing the spring pressed scribing element in its cartridge with the cartridge in the cartridge support held in the clamp on the other radially adjustable arm of the other pair of leaf springs.

FIGURE 6 is a fragmentary section taken substantially on line 6-6 of FIGURE 2 showing the mounting of the two pairs of leaf springs on the mounting block fixed to the tubular center support.

FIGURE 7 is a fragmentary view of the fixed scribing point in its closest relation to the drop center shaft to illustrate the arrangement which prevents physical connited States Patent tact of the scribing point of the scribing element with the drop center and showing the sharp angle of the cartridge support to permit drawing circles of small radius.

FIGURE 8 is a detail of the less sharply angled cartridge support for supporting the cartridge which carries the spring pressed scribing element so that both the fixed and the spring pressed scribing elements may operate simultaneously without excessive force.

FIGURE 9 is an elevation of one of the replaceable scribing elements which is usable in either cartridge.

Referring more particularly to FIGURES 1 to 9, a scribing device for simultaneously making two circles of different diameters such as for circuit pads includes a drop center type compass. The compass includes a tubular center support 200 on which a mounting block 201 is fixedly secured adjacent to and spaced from one end, the other end being externally tapered, a stud receiving recess being provided intermediate the ends for receiving the head of a clamp screw. A first radial arm includes a pair of leaf springs 202, 203 secured by suitable screws 204, 205 which pass through apertures in the leaf springs and are threaded into threaded openings in the mounting block 201. The outer ends of the leaf springs are secured to a clamp member 206 which is secured to the outer end of leaf spring 203 by a shouldered and externally and internally threaded sleeve 207 passing through aligned apertures and threaded into an upstanding portion of the clamp 206 with the shoulder abutting the leaf spring 203. The outer end of the clamp 206 is provided with a bore for receiving the shank of a cartridge support and such bore includes diametrically opposite cut-away portion to provide for a clamping action of the clamp in a radial direction. The spring 202 extends to the lower end of the clamp 206 and is secured thereto by a headed screw 208 which is threaded into the adjacent portion 209 of the clamp 206 and passes freely through an aperture in the outer portion of the clamp and a knurled nut 210 is threaded onto the outwardly extending portion of the headed screw 208 and serves to provide the clamping action.

An aligning stud 211 is also provided on the clamp 206 and projects through a registering aperture in the leaf spring 202 thereby providing for accurately maintaining the clamp ina definite relation to spring 202. To move the clamp 206 outwardly a thumb screw 212 is threaded through the shouldered sleeve 207 and abuts a groove on the adjacent side of the tubular center support 200 whereby rotation of the screw 212 provides for radial adjustment, the leaf springs 202, 203 normally urging the clamp toward the tubular center support 200.

Mounted in the clamp 206 is a slightly angled cartridge holder 213 which has a split shank 214 of cylindrical outer confirmation with the split shank adapted to straddle the clamping screw 208 thereby preventing relative rotation, the cartridge holder being clamped in position by the clamping action of thumb screw 210. The opposite or cartridge holding end of the cartridge holder is provided with a bore 216 split as indicated at 215 with the bore arranged at an angle to the shank of the cartridge holder so that in normal scribing a cartridge 217 and the scribing element 218 therein will be inclined in the direction of movement as the compass is rotated clockwise as viewed from above at an angle of w. to the plane of the scribe coat surface 219. It will be noted that the cartridge 217 is generally cylindrical in outside configuration with the lower end being conically tapered and the cartridge is slidable in the bore 216. The cartridge 217 is provided with a bore which includes intermediate bore 220 whch snugly and slidably receives the scribing ele ment 218 with a reduced bore or at the lower end and an enlarged internally threaded bore 221 at the upper end and an externally threaded cap 222 closes the upper end of the cartridge bore and retains a spring 223 positioned between the cap 222 andthe adjacent end of the scribing element 218 urging the scribing element to the projected position shown in FIGURE while permitting the scribing element 218 to move against the bias of the compression spring 223 to provide a substantially uniform scribing force on the scribing point 224 at the free end of the small diameter portion of the scribe element 218. The position of the cartridge 217 in cartridge holder 213 is suitably adjusted the thumb screw 225 passing freely through one split portion of the cartridge support threaded into the other split portion produces a clamping action retaining the cartridge 217 in any adjusted position. It will also be noted in FIGURE 8 that the split cartridge receiving portion of the cartridge support 213 in a plane at right angles to the plane shown in FIGURE 20 shows that the cartridge receiving bore 216 and scribing element 218 are arranged at an angle a to the split shank 214 and the scribing element 218 lies in a plane generally perpendicular to a radius line perpendicular to the axis of the center support 200.

A drop center shaft 226 similar to drop center shaft 63 previously described is slidably mounted in the tubular center support 2% and is manipulated by the knob 227 at the top, the downward movement being limited by an adjustable collar 228 while upward movement is limited by a collar similar to the collar 67 previously described engaging the threaded bushing 229 threaded into the top of tubular center 2110 reacting against the collar to limit the axial movement of the drop center 226. It will be noted that the drop center 226 has a portion of reduced cylindrical shape 239 and a surface contact point 64 at the free end thereof.

The other radial extending arm of the double arm compass is made substantially similar and the parts thereof are identified by the same reference numerals with a suffix F to indicate fixed scribing element. However, there is a difference in the angle B (FIGURE 8) of the scribing element 218F being substantially greater than angle A of the spring pressed scribing element 218 so that the scribing point 224F can be located substantially closer to the drop center point 64- to provide for scribing a very small circle. Also, the scribing element 218 is mounted in fixed relation by means of a cylindrical rod 232 which reacts between the cap 222F and the scribing element 218F.

With reference to FIGURE 7 it will be noted that the arrangement and dimensions of the parts provide for engagement of the full diameter portion 226 of the drop center with the other split portion 233 of the cartridge holder and also by the engagement of the lower conical portion 234 of the drop center tubular support 200 with the said other split portion 223 of the cartridge holder and the lower end of the large diameter portion of the drop center 226 may engage the lower conical portion 235F of the cartridge holder 217F thereby preventing physical contact between the center point 64 and the scribing point 224F avoiding damage and breakage of the parts while permitting the scribing point 224F to be as close as possible to the axis of the drop center 226 as illustrated in FIGURES l7 and 22. The adjustment of scribing point 224F is such that it lies in a plane including the axis of drop center 226 and is movable in such plane during any radial adjustment thereof so that the smallest circle can be scribed without physical contact of scribing point 224F with center 226. Even though cartridge 217 is improperly adjusted and extend excessively the scribing point of 22 2 1 cannot contact the drop center.

It is believed that the operation of the double armed scribing compass of FIGURES 1-9 should be obvious and it will be apparent that the drop center 226 is arranged to extend beyond a plane perpendicular to the center axis and located beyond the scribing points 224 and 224F. The center point 64 thereof is placed on the scribing surface 219 and the tubular center support 200 with the scribing points 224, 224F are moved downwardly until both scribing points engage the scribing surface 2119. Upon a single rotation of the double armed scribing device concentric circles are formed and the scribing pont 224F engaging the scribing surface 219 determines the extent of axial movement of the radial arms with the scribing points toward the scribing surface 219 while the spring pressed scribing point 224 may be pushed upwardly against the compression spring 223 to scribe on the scribing surface 219 simultaneously with fixed scribing point 224E. This also permits satisfactory scribing even though the center 226 is not held perpendicular to the scribing surface 219. If the pressure on resiliently pressed scribing point 224 is insufiicient, the cartridge 217 may he slid downwardly in its holder to thereby cause the point 224 to engage scribing surface 219 while fixed scribing point 224E is substantially above the scribing surface 219 to increase the force of the pressure on scribing point 224 on the scribing surface 219. If the scribing force on resilently pressed scribing point 224 is too great, such force may be reduced by retracting the cartridge 217 into the cartridge holder 213.

It will be noted that the double armed scribing device is normally rotated in a clockwise direction as viewed from the above causing the scribing points to be pulled or dragged thereby avoiding any detent action which might result from pushing of the scribing points on the scribing surface 219 as a result of counter-clockwise rotation; also the threads of bushing 229 are right hand threads to permit the flange thereof to be used in clockwise rotation. It will also be evident that the radius between the axis of drop center 226 and the fixed scribing point 224E will be constant because of the fixed mounting of the scribing point 224E It will also be apparent that the scribing point 224 is movable along its length in its cartridge 217 but that the plane of operation of the scribing element 218 and point 224 is so close to a plane perpendicular to a radius perpendicular to the axis of drop center 226 that variations due to the movement of the scribing point into the cartridge do not materially change the effective scribing radius of scribing point 224 for any selected adjustment.

It will be apparent that various changes may be made within the spirit and scope of the invention within the valid interpretation of the claims.

What is claimed is:

1. A scribing device comprising a tubular center support, a mounting block fixed to said tubular support, a pair of leaf springs mounted on diametrically opposed portions of said mounting support, a clamp mounted at the outer end of each pair of springs, means to move the clamps radially outwardly from the tubular center support against the bias of the springs, a sharply angled member mounted in one clamp, a less sharply angled member mounted in the other clamp, a scriber receiving cartridge slidably mounted in each of said angled members and adjustably retained therein, a shouldered scribing element in each cartridge, means to positively retain the scribing element in fixed position in said sharply angled member, a spring mounted in the other cartridge and urging the shouldered scribing element to an outwardly projected position, a threaded screw mounted on the opposite end of said second cartridge and engaging said spring thereby urging said second scribing member to its projecting position, a drop center shaft slidably mounted in said tubular center support, means to limit the axial movement of said drop center shaft within said tubular center support whereby the radial distance of said fixed scribing element from the axis of said drop center shaft may be adjusted for a circle of small radius closely adjacent the point of the drop center shaft and the spring urged scribing element will lie in a plane substantially perpendicular to a radius from said drop center shaft whereby variations in projection and retraction of said spring pressed scribing element during normal use will not materially alter the radius thereof.

2. A drop center compass comprising a tubular member, a drop center shaft slidably mounted in said tubular member, a pair of arms one arm disposed on one side of the tubular member and the other arm disposed on the other side of the tubular member, each arm connected to said tubular member at one end, means to adjust the other end of each arm toward and away from the tubular member, a first scriber point fixedly mounted on the free end of one of said arms, a second scriber point yieldably mounted on the free end of the other arm and diametrically opposite to said first scriber point and urged outwardly beyond the axial extent of the fixed scriber point when the drop center shaft is substantially perpendicular to a plane supporting surface such as a drafting board, means to manipulate the drop center to contact a surface to be scribed and means to move the pair of arms with the fixed scriber point and the yieldably mounted scriber point toward and from the supporting surface whereby the yieldably mounted scriber point engages the supporting surface prior to the engagement of the fixed scriber point and two circles of different radii may be drawn simultaneously by rotation of the compass with the desired pressure on each scriber point.

3. The invention according to claim 2 in which the second scriber point is the end of an elongated scriber element having a shoulder intermediate its ends which scriber element is mounted in an open ended hollow cylindrical cartridge having a reduced bore at one end for passage of the scriber point end portion of the scriber element and a spring is mounted within the cartridge abutting the other end of the scriber element and held in place by a cap closing the other end of the cartridge.

4. The invention according to claim 2 in which the second scriber point is the point of an elongated scriber element and the elongated scriber element lies in a plane generally perpendicular to a plane defined by said tubular member and said other arm and also lies at an acute angle to the plane defined by said tubular member and said other arm.

5. The invention according to claim 4 in which the elongated scriber element carrying the second scriber point is provided with a shoulder and is supported in a cylindrical cartridge adjustably mounted on the said other arm and a spring reacts between said cartridge and said elongated scriber element.

6. The invention according to claim 5 in which the first scriber point is the end of an elongated shouldered scriber element and is mounted in a cylindrical cartridge adjustably secured to the free end of said one arm.

7. The invention according to claim 6 in which the cartridge and elongated shouldered scriber element lie in a plane perpendicular to a plane defined by said one arm and said tubular member and lies at an acute angle to the plane of said one arm and said tubular member.

8. A drop center compass comprising a tubular member, a drop center shaft slidably mounted in said tubular member, an arm connected at one end to one end of said tubular member, means to adjust the other end toward and away from the tubular member, a first scriber fixedly mounted on said other end of said arm, a second scriber diametrically opposite said first scriber and yieldably mounted on said compass and urged outwardly beyond the axial extent of the first scriber when the drop center shaft is substantially perpendicular to a plane supporting surface such as a drafting board, means to move the pair of scribers toward and away from the supporting surface whereby the yieldably mounted scriber engages the sup porting surface prior to engagement of the fixed scriber.

References Cited UNITED STATES PATENTS 1,191,725 7/1916 Paulsen 3327 2,442,185 6/ 1948 Szerenyi 33-27 2,551,747 5/1951 Ille 33-41 2,557,500 6/1951 Fairbanks 3327 FOREIGN PATENTS 175,890 10/ 1906 Germany.

276,713 7/ 1914 Germany.

338,756 7/1921 Germany.

246,081 1/ 1926 Great Britain. 1,153,005 9/ 1957 France.

LEONARD FORMAN, Primary Examiner. HARRY N. HAROIAN, Examiner.

Claims (1)

1. A SCRIBING DEVICE COMPRISING A TUBULAR CENTER SUPPORT, A MOUNTING BLOCK FIXED TO SAID TUBULAR SUPPORT, A PAIR OF LEAF SPRINGS MOUNTED ON DIAMETRICALLY OPPOSED PORTIONS OF SAID MOUNTING SUPPORT, A CLAMP MOUNTED AT THE OUTER END OF EACH PAIR OF SPRINGS, MEANS TO MOVE THE CLAMPS RADIALLY OUTWARDLY FROM THE TUBULAR CENTER SUPPORT AGAINST THE BIAS OF THE SPRINGS, A SHARPLY ANGLED MEMBER MOUNTED IN ONE CLAMP, A LESS SHARPLY ANGLED MEMBER MOUNTED IN THE OTHER CLAMP, A SCRIBER RECEIVING CARTRIDGE SLIDABLY MOUNTED IN EACH OF SAID ANGLED MEMBERS AND ADJUSTABLY RETAINED THEREIN, A SHOULDERED SCRIBING ELEMENT IN EACH CARTRIDGE, MEANS TO POSITIVELY RETAIN THE SCRIBING ELEMENT IN FIXED POSITION IN SAID SHARPLY ANGLED MEMBER, A SPRING MOUNTED IN THE OTHER CARTRIDGE AND URGING THE SHOULDERED SCRIBING ELEMENT TO AN OUTWARDLY PROJECTING POSITION, A THREADED SCREW MOUNTED ON THE OPPOSITE END OF SAID SECOND CARTRIDGE AND ENGAGING SAID SPRING THEREBY URGING SAID SECOND SCRIBING MEMBER TO ITS PROJECTING POSITION, A DROP CENTER SHAFT SLIDABLY MOUNTED IN SAID TUBULAR CENTER SUPPORT, MEANS TO LIMIT THE AXIAL MOVEMENT OF SAID DROP CENTER SHAFT WITHIN SAID TUBULAR CENTER SUPPORT WHEREBY THE RADIAL DISTANCE OF SAID FIXED SCRIBING ELEMENT FROM THE AXIS OF SAID DROP CENTER SHAFT MAY BE ADJUSTED FOR A CIRCLE OF SMALL RADIUS CLOSELY ADJACENT THE POINT OF THE DROP CENTER SHAFT AND THE SPRING URGED SCRIBING ELEMENT WILL LIE IN A PLANE SUBSTANTIALLY PERPENDICULAR TO A RADIUS FROM SAID DROP CENTER SHAFT WHEREBY VARIATIONS IN PROJECTION AND RETRACTION OF SAID SPRING PRESSED SCRIBING ELEMENT DURING NORMAL USE WILL NOT MATERIALLY ALTER THE RADIUS THEREOF.

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