US3587362A - Drilling jig - Google Patents

Abstract

A DRILLING JIG IN WHICH SEVERAL DRILL BUSH HOLDERS ARE ADJUSTABLY MOUNTED OVER A BASEPLATE. EACH HOLDER IS APPROXIMATELY U-SHAPED AND NORMALLY FASTENED TO THE BASEPLATE BY ITS BIGHT PORTION. A SCREW CONNECTING THE TWO LEG PORTIONS OF THE HOLDER PERMITS THE FREE ENDS OF THE LEG PORTIONS TO BE MOVED TOWARD AND AWAY FROM EACH OTHER FOR CLAMPING A SPLIT RING HELD BETWEEN THE FREE ENDS ABOUT A DRILL BUSH. THE HOLDERS THE POSITIONED ON THE BASEPLATE BY MEANS OF A GAGE HAVING TWO ARMS ELONGATED AT RIGHT ANGLES TO EACH OTHER AND CARRYING RESPECTIVE SLIDES. COOPERATING ABUTMENTS ON ONE SLIDE AND ON THE BASEPLATE DETERMINE THE PORTION OF THE GAGE WHICH IS GUIDED RELATIVE TO THE BASEPLATE, AND A CONICAL ELEMENT ON THE OTHER SLIDE MAY BE ENGAGED COAXIALLY WITH A DRILL BUSH IN THE HOLDER TO BE POSITIONED.

Description

United States Patent Inventor Viktor Clio Zurich, Switzerland Appl. No. 770,711 Filed Oct. 25. I968 Patented June 28, i971 DRILLING .IIG 5 Claims, 7 Drawing Figs.

US. Cl. 408/115, 24/ 1 9.241257 ht. B23b 47/28, 1323b 49/04 Field ofSeareh 24/19, 257; 77/62 Relerences Cited UNITED STATES PATENTS 820,965 5/1906 Froggatt 77/62 1,235,031 7/l9l7 Holmgren 77/62 25 o O F 2| 3 l0 4 i n= a; seeeee- Primary Examiner-Francis S. Husar ABSTRACT: A drilling jig in which several drill bush holders are adjustably mounted over a baseplate. Each holder is approximately U-shaped and normally fastened to the baseplate by its bight portion. A screw connecting the two leg portions of the holder permits the free ends of the leg portions to be moved toward and away from each other for clamping a split ring held between the free ends about a drill bush. The holders the positioned on the baseplate by means of a gage having two arms elongated at right angles to each other and carrying respective slides. Cooperating abutments on one slide and on the baseplate determine the position of the gage which is guided relative to the baseplate, and a conical element on the other slide may be engaged coaxially with a drill bush in the holder to be positioned.

PATENTED JUN28 I971 SHEET 1 BF 2 I :NTUR. 1/ K To BY mm M W4 d w CHO AGE/W's PATENTED JUN28 19m SHEET 2 [IF 2 OOOOQOQO INVEN'I'UR. K R CH BYz/QM [Mag [bum/LL AGE/v75 DRILLING JIG The present invention concerns a device designed to solve in a general manner the most varied problems arising in connection with a drilling and boring device, to an extent which is not feasible with the known systems. The chief object here is the quick provision of a ready-for-use tool for small production batches. The main feature of the new device is that, for universality of application, it consists of a combination of the following new elements, in particular that it comprises interchangeable clamping rings which serve to clamp the drill bushes of various sizes and which coact with the bush holders and the holder supports and which can be set to the required position by means of a coordinate sliding gauge, while a spindleless coarse and fine fixing system serves to fix the work, the arrangement being such that the said two fixing elements are mounted as a whole on a switchable ball bearing with a view to facilitating the centering of the drills, and that in addition an adjustable angle scale dial is provided for the setting and measuring of interrelated boreholes on round workpieces.

With the said invention, the following new results have been achieved in toolmaking:

l. The known adjustable bush holders only permit bushes of a particular size and of the same outside diameter to be fixed, so that a whole number of different bush holders is required to accommodate bushes of various sizes. The new universal device differs from these known systems in that it has a universal horseshoe-shaped bush holder which can take all the usual sizes of bushes by means of interchangeable clamping rings.

2. With the known bush holders, the bush is fixed in a bore inside the relatively large holder head, so that two bush holders can only be moved so near to each other as the width of the holder head permits, so that for closely spaced bores they cannot be used at all. This drawback has now been eliminated by the new thin-walled clamping ring coacting with the new bush holder, because now the bushes are located at the open end of the horseshoeshaped holders and thus stand clear except for the width of the holder shank tip. This permits the bushes to be moved together very closely, i.e. almost until they touch, owing to the thinness of the clamping ring wall.

. The new device has yet another advantage in that, for the fixing of the work, it is mounted over a new spindleless fine-fixing system with self-acting parallelism without lateral guide. As is known, in a fixing tool, such as a vice, the parallelism of the two fixing jaws is of paramount importance. To ensure this, the fixing jaws must have a side guide of maximum length and strength, and this also in volves expensive machining to close tolerances. A long guide of that type takes up a great deal of room and thus reduces the fixing width of the fixing tool. In the new device, moreover, the tiltable jaw also has a down-pulling effect.

A special coordinate sliding gauge permits the bushes to be set very quickly to the exact positions required.

. For easier centering, the'whole unit can be engaged with a switchable ball bearing and disengaged again.

6. The adjustable angle scale dial was devised for the quick setting and measuring of interrelated boreholes on round workpieces.

An embodiment of the said invention is illustrated by way of example in the attached drawings, wherein:

FIG. 1 is a top-view of the whole device; FIG. 2 is a longitudinal section through the device along line A-B;

FIG. 3 is a top-view of the coordinate sliding gauge;

FIG. 4 is a crosssection through the said gauge along line C-D;

FIG. 5 is a diagram of the angle setting unit for round workpieces;

FIG. 6 shows the pointer fastening means;

FIG. 7 shows the switching unit of the ball bearing.

BASIC UNIT The basic unit is shown in FIGS. 1 and 2. The base of the device comprises a baseplate l, a fixed jaw 2, a tiltable jaw 3, a stop-plate 4 and also several beams I7, 18 fixed to the baseplate by means of columns 21. Mounted on U-shaped beams are the bush holders 5, whose leg portions are provided at the free. ends with two opposed notches conformingly receiving the dovetail-shaped, split fastening projection 8 of a split clamping ring 7. Tightening a screw 10 closes the clamping ring 7 about a drill bush 6. The bush is then brought into the position required and fixed on the beams 17 and 18 by bolts 13 and I4 engaging the bight portion of each holder 5. The beams 17 and 18 each present a row of threaded holes 20 and have throughout their length a groove 15 of angular cross section adapted conformingly to receive the hook-shaped head of each bolt 14 to permit the latter to be moved and fixed at any point so as to fix the bush in any position required. The beams I7 and 18 can be fixed to the baseplate l at various heights by means of interchangeable columns 21.

The two jaws 2 and 3 serve to fix the workpiece. Jaw 2 is fixed to baseplate 1, and jaw 3 is tiltably arranged on stopplate 4. Fixed to the rear of stop-pliate 4 is a stop-bar 23 against which rests the tiltable jaw 3, which is flexibly held by two bolts. Arranged in the upright section of jaw 3 are two springs 27 side by side, which keep the upright section in a slightly raised position. Stop-plate 4 serves for the coarse setting on the base-plate. Baseplate 11 presents two rows of threaded holes, 9 disposed at regular intervals. Stop-plate 4 has two slots 25 aligned with respective rows of holes 9 and permitting the plate to be fixed in any position according to workpiece 30. For fine fixing, the horizontal section of jaw 3 presents a bolts 28 which can be screwed into the threaded hole of stop-plate 4. Tightening the bolt 28 tilts jaw 3 forwards, thus fixing and concurrently pulling down the workpiece. Owing to the tilt, however, the work-fixing surface of jaw 3 is not parallel to the opposite fixing surface. To remedy this, the former surface is provided with a number of halfround grooves, into which, before fixing the work, are placed half-round bars 29 with the flat side against the workpiece. This arrangement ensures parallelism of work-fixing through automatic turning of the said bars.

SETTING THE DRILL BUSH To permit the drill bush 6 to be set to the position required for the work, a coordinate sliding gauge has been devised. This is shaped as a right angle and is provided like an ordinary sliding gauge with graduations in both the ordinate and the abscissa directions and carries on each arm a slide 48, 49, either with or without vemier. Slide 48 serves as a stop for the ordinate at screw 54 fixed to the end of beam 17. Screw 54 thus serves for the fine setting of the zero position of the sliding gauge. Slide 49 is provided underneath: with an angle piece 50 connected with acone tip holder 51, which holds a cone tip 52 upright and resiliently by means of a spring 53.

The coordinates are set as follows:

Required is a borehole whose center, measured from the stop side (base line) in the drawing, has an ordinate of 42 mm. and an abscissa of 57 mm. The procedure now is to set the particular coordinates, viz. 42 mm. by slide 48, 57 mm. by slide 49, and then to place on the cone tip 52 the bush 6 held by bush holder 5, thus automatically centering the bush. The bush holder can then be screwed fast at a suitable point along the beam, so that bush 6 is fixed exactly in the position given in the drawing. Arranged below beam 1.7 and along it is a stopbar 55, which serves together with jaw 2 as a stop for the workpiece and together with anglepiece 50 of slide 49 as a support for the coordinate sliding gauge in measuring position. The coordinate sliding gauge may also be composed of two commercial sliding gauges fitted together.

ADJUSTABLE ANGLE SCALE When shafts of various diameters are to be provided with bores arranged radially and spaced at specific angles, the problem of exact angular setting arises. To solve this problem, the invention includes an adjustable angle scale dial, which can be brought into the position required by sliding it along a guide member according to the diameter of the shaft to be machined. As all such shafts, regardless of diameter, are fixed between stop-surface 61 of the bush and jaw 2, all their center axes lie in the angle-bisecting plane 63 of stop-surface 62 of jaw 2 and stop-surface 61. Accordingly, a bar 65 presenting a scale 66 along its length corresponding to the various shaft diameters is arranged at the side of jaws 2 and at an angle of 45 degrees to the baseplate and rigidly connected to the baseplate and beam 18, in such a manner that the semicircular angle scale 60 can be moved thereon in such a way that its center comes to lie on the center axis of the shaft to be machined and can be fixed there by a screw.

A pointer 70 fixed to a cylindrical permanent magnet 69 or a prismatic permanent magnet 68 can now be magnetically fixed to the side of the shaft or, with longer shafts, on the circumference thereof, so that, being radial to the shaft, it indicates on the scale the exact angle through which the shaft was turned or should be turned. With nonmagnetic work pieces, fixing can be effected by a mechanical, fork-shaped clamp, which need not be specified here.

SWITCI-IABLE BALL BEARING SYSTEM A problem in the drilling or boring of heavy workpieces is that the drill tends to deviate from the center in the bush. As is known, exact centering of the drill in the bush is very difficult in the case of relatively small diameters. For this reason, the new device is supported on a switchable ball bearing system, so that the rolling of the ball bearing reduces the friction of the whole device and thus facilitates centering. After centering, the ball bearing can be disengaged, so that the support plate 33 is lowered to the machine base and seated fast again. The halls lie in inward tapering holes 35 in support plate 33 in such a way that the'downthrust of intermediate plate 32 pushes them in and down far enough for them to project below and act as a rolling system on the machine base.

The downthrust of intermediate plate 32 is effected by the wedge action of two relatively displaceable elements which, for low friction, act in conjunction with balls interacting with two narrow strips 40 or a broad plate 41. The strips or the plate present several holes 42 whose diameter is slightly smaller than that of balls 34, for the purpose of receiving the latter. As the friction near the top of the balls is very slight, the balls can be easily pushed out of the holes by displacing the strips or the plate. Balls 34 are arranged as near along the edge of baseplate l as possible, for even support of the latter.

In FIG. 7, a shows the ball still in the hole of the strip, while b shows the ball as pushed out by displacement of the strips. In accordance with the holes in the strips or the plate, the intermediate plate 32 has as many, but deeper holes for receiving the balls 34. After displacement of the strips or the plate, all balls 34 are pushed down. Intermediate plate 32, which has received balls 34, is thrust down accordingly. This process pushes all balls 35 under the intermediate plate slightly out of the support plate 33 for rolling engagement with the nonillustrated machine base. Displacement ofthe strips or the plate is effected by swiveling a ball-handle 38, 39, which acts by an eccentric stud 37 in the bore of a lever 36 or in the bore of the said plate 41. The coacting lever is pivotally mounted on a pin 36a fixed to baseplate 1, and its two ends are movably connected with the said strips 40, so that the two strips move in opposition to each other, while plate 41 only moves in one direction, with the result that balls 34 are pushed out, as mentioned. The switching system can also be designed in such a way that the intermediate plate 32 stays fixed or is entirely eliminated, i.e. that balls 35 come in direct contact with baseplate 1. Support plate 33 is thinner than the ball and is held against the baseplate by screw 44 and a spring not specified, so that the balls project slightly during centering, so that baseplate 1 can roll on the machine base directly by means of balls, 35. After centering, swiveling the ball-handle 38, 39 causes the strips 40 to press balls 34 and support plate 33 down, so that the drilling and boring device is again seated fast on the machine base.

' ADDITION TO WORK FIXING ELEMENTS Fine fixing of the work, instead of being effected by tilting the jaw 3, can be effected by the relative displacement of two wedge jaws, not specified, coacting with jaw 3, in that the displacement of the wedge jaws, one lying on the other, is effected by means of a lever or an eccentric, and as both jaws lie flat against each other with their whole surface, there is no danger of any canting, although there is no lateral guidance, in particular for workpieces requiring a broad-fixing surface. Of course, ordinary vices can be used instead of the spindleless fine-fixing system.

The clamping ring 7 can also be made of spring steel, in

which case the opened dovetail-shaped projection can be brought into suitable shape directly by bending the spring steel.

Beams 17, 18 are each provided below and along their full length with an angled groove 15 adapted to the hook-shaped head of bolt 14, to permit bush holders 5 to be fixed at any point.

I claim:

1. A drilling jig comprising, in combination:

a. a baseplate;

b. a plurality of holder members;

c. mounting means for releasably mounting said holder members on said baseplate in a plurality of positions relative to each other,

1. each of said holder members being substantially U- shaped and having a bight portion adapted to be mounted on said base plate by said mounting means and two elongated leg portions having respective free ends remote from said bight portion;

d. threaded means on each holder member connecting said leg portions for moving said free ends toward and away from each other; and

e. a circumferentially split-clamping ring adapted to receive a drill bush therein,

1. said ring having a split annular portion and a split, substantially dovetail-shaped fastening portion, the two parts of the split fastening portion being connected by the annular portion,

2. each of said free ends being formed with a recess opposite the corresponding recess on the other free end of the holder member,

3. said recesses being arranged simultaneously to engage said parts of said fastening portion in clamping engagement when said free ends are moved toward each other by said threaded means.

2. A jig as set forth in claim 1, wherein said annular portion freely projects from said holder member when said fastening portion is clampingly engaged in said recesses, said annular portion being of resilient material.

3. A jig as set forth in claim 1, wherein said recesses are notches in said free ends transverse to the direction of elongation of the respective leg portions.

4. A jig as set forth in claim 1, further comprising positioning means for positioning each holder member, said positioning means including a gauge having two elongated arms fixedly connected transversely to each other, guide means for guiding movement of said gauge relative to said baseplate, two slides longitudinally movable on said arms respectively, cooperating abutment'means on said baseplate and on one of said slides for establishing the position of said gauge, and a conical element mounted on the other slide for movement transversely to the corresponding arm for coaxial engagement with a drill bush held by the holder member to be positioned.

formed with a longitudinal groove of angular cross section ex tending substantially over the entire length of the beam member, said threaded member having a hook-shaped head conformingly engageable with said groove.

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