US2316483A - Contour scriber - Google Patents

Description

April 1 9 3; L. F. WILLIAMS 2,316,483

CONTOUR S CR IBER Filed June 2, 1941 INVENTOR, I 21x64 9; me.

'Arromveys Patented Apr. 13, 1943 UNITE D STATES PAT EN T O F FI'C E CONTOUR SCRIBER Luther F. Williams, Oakland, Calif.

Application lime-2, 1941, Serial N0. 396,369

'4 Claims.

The present invention relates to devices for making contour drawings of irregular objects such as the heads of railway rails and the treads and flanges of car wheels.

The principal objects of the invention are to provide an instrument that is readily portable and quick and easy to use, that hasgreat accuracy, that has a minimum number of movable parts, and that can be manufactured at reasonable cost. Other objects and advantages of the invention will become apparent from the following description, which should be read with the understanding that changes may be made in the form, construction and arrangement of the several parts herein shown and described, without departing from the spirit of the invention as defined in the claims hereto appended.

Reference will be made to the accompanying drawing, wherein- Fig. 1 is a front elevation of a preferred'embodiment of the invention as applied to a railway rail, the rail being shown in section.

Fig. 2 is a top View of the same.

The reference numeral ll designates alplaten, preferably in the form of a fiat plate of steel or some other stiff metal, having a smooth front surface against which a card or sheet of paper 12 is held by spring clips l3. The plate H is mounted upon a clamp of suitable form for attachment to the object whose contour is to be drawn. For example, when the instrument is intended principally for scribing rail heads, the simple clamp herein illustrated may be used, comprising a channel member M with set screws It to clamp upon the head of the rail 15. The late II is secured to the channel member I' l by screws l1 and a brace I8, in such a manner that it stands vertically above the rail in a plane at right angles thereto. The lower edge of the plate I I is cut out, as at l9 to enable it to fit partially over the rail head.

Near each side edge of the plate I I, and secured to it, is a vertical guide bar 20. The guide bars are spaced from the surface of the plate by spacers 2!, and secured thereto by screws 22. A slide 23 is movably mounted on each guide bar, and is retained in sliding relation thereon by channel guides 24 secured to said slide and overlapping the edges of the guide bar. Near the upper end of each slide 23, there is pivotally mounted, upon a screw 25, a pencil carrying arm 26. Near the lower end of each slide there is mounted, upon a pivot screw 21, a scribing or feeler arm 28. The two arms 26 and 28 are connected by a link 29 pivoted on screws 30. The slide 23, the arms 26 and28, and the link 29 form a parallelogram, so that the movement of the pencil carried by the arm .26 corresponds to the movement of the feeler carried by the arm 28, regardless of whether the movement is linear upon'the guide bar 20 or arouate about the-pivots 25 and. 21.

The feeler comprises a sickle shaped piece of flat steel 3! with a hardened point 32, and is secured to the end of a cylindrical shank 33 which "is mounted "for both rotary and endwise movement in lugs 34 projecting forwardly from the arm 28. A knob 35 is secured to the outer end of the shank 33, and the inner end of said kn'ob forms-a shoulder provided with two'diametrically opposite teeth 36, which engage notches in the outermost lug 34 to prevent-rotation of theshank and feeler. A spring 31 surrounding the shank 33, between said outermost lug 34 and a collar 38 on said shank, maintains the teeth and notches in engagement. The feeler point-32 is positioned in line with the axis of the shank 33, and the teeth 36 and corresponding notches are so placed that the feeler :is parallel with the face of the plate H, with its point 32 directed either up or down.

The pencil arm 26 has secured to its 'back, at 39, a fiat spring 40 which extends beyond the inner end of the arm 26 and carries a suitable chuck '41, of any'well known form, adapted to hold a pencil lead 42. The spring 46 is bent so that it springs away from the arm '26 and keeps the pencil "in contact with the paper. A screw '43 having laknurled knob 44 on its forward end,

is threaded through the arm 26, passes freely through an enlarged hole in the spring it, and has'a shoulder '45 engaging the rear face "of said spring. By unscrewing-the screw "43, the pencil 42 can be raised off the paper.

To :hold the arms immovable when not in use, the rear end of the screw i3 is threaded, 'as at 46, to engage a threaded socket formed in a stud 4'! projecting from the plate ll near its top. For convenience, the stud 41 forms one of the holding screws for the paper clip 13. The height of the stud 47 is such that when the screw 43 is screwed all the way home into its socket, the spring 40 will be at the proper distance away from the plate for normal drawing. Therefore, when the screw 43 is in said socket, the pencil 42 can be set in its chuck 4| so that it just touches the plate H. When the screw 43 is backed out, to free it from the holding stud 41, the pencil will be raised on" the paper, and when said screw is again screwed in to its inner limit,

there will be sufficient clearance for normal drawing without too much tension in the spring 40.

The feeler and tracing mechanism as described above is duplicated at both sides of the instrument, as shown in Fig. 1, one set of arms and their carrying slide being used to trace one side of the rail and the other set for the other side. The arms are of such length that the feeler points 32 and pencils 42 overlap slightly in their positions at the center of the paper when their respective arms are horizontal.

To operate the instrument; it is first clamped upon the rail head and a sheet of paper is placed against the plate ll under the spring clips l3. While the arms 26 are locked in upper position, the pencil leads are adjusted in their chucks 4| so that their points touch the plate ll. One of the screws 43 is then backed out, releasing its arm 26 and raising the pencil off the paper. With the feeler point directed downwardly, the slide 23 is lowered until the feeler point touches the top of the rail when the feeler arm is about horizontal. The screw 43 is screwed in to its limit, lowering the pencil upon the paper. Then by a compound movement, raising the slide and swinging the feeler arm down, the feeler point is caused to follow the top of the rail outwardly to its corner.

When a position is reached at which the feeler point can no longer follow the surface of the rail as it curves downwardly, the feeler shank 33 is rotated half a turn by means of its knob 35. Then by moving the slide 23 downwardly,

the feeler point is moved down along the side surface of the rail head and swung inwardly to follow its under surface and the side of the web. During these movements of the feeler in contact with the surface of one longitudinal half of the rail, the pencil has traced an exact duplicate of the contour of said surface on the paper.

When enough of the web of the rail has been scribed, the screw 43 is backed out to raise the lead, and the slide 23 and arm 26 are raised and locked in inoperative position. The other arm is then released and the process repeated to trace the other half of the rail.

only one slide and one set of arms, arranged in such a position that the feeler point can reach all parts of the surface. The clamp, of course, must be suitably designed to hold the instrument rigidly in proper relation to the object.

The essential feature of the invention, viz;

the combination of a linear slide and pivotal arms to produce the necessary compound movement, enables a more compact and rigid instrument than the customary pantograph type in which all parts are pivoted, and lends itself better to the more exacting demands of field use.

I claim:

1. In a contour scriber having a flat platen with means for clamping the same to the object to be scribed and means for holding a sheet of paper on said platen, movable feeling and tracing arms interconnected for simultaneous corresponding movement to trace the contour of the object on the paper, a resilient extension carried by said tracing arm, tracing means carried by said extension, an adjusting member carried by said arm [for raising said tracing means off the paper, and locking means operated by said adjusting member for holding the arms stationary.

2. In a contour scriber having a fiat platen with means for clamping the same to the object to be scribed and means for holding a sheet of paper on said platen, movable feeling and tracing arms interconnected for simultaneous corresponding movement to trace the contour of r the object on the paper, a fiat spring secured to said tracing arm, tracing means carried by said spring, an adjusting member mounted in said am for moving said spring toward and away from the paper, and locking means operated by said adjusting member for holding the arms stationary.

3. In a contour scriber having a fiat platen with means for clamping the same to the object to be scribed and means for holding a sheet of paper on said platen, movable feeling and tracing arms interconnected for simultaneous corresponding movement to trace the contour of the object on the paper, tracing means resiliently mounted on said tracing arm for movement toward and away from the platen, and locking means actuated simultaneously with the last mentioned movement of said tracing means for holding the arms stationary with respect to the platen.

4. In a contour scriber having a flat platen with means for clamping the same to the object to be scribed and means for holding a sheet of paper on said platen, movable feeling and tracing arms interconnected for simultaneous corresponding movement to trace the contour of the object on the paper, tracing means resiliently mounted on said tracing arm for movement toward and away from the platen, a locking member fixed with respect to the platen, and a movable locking member carried by one of said arms and positioned for separable engagement with said fixed locking member to hold the arms stationary.

LUTHER F. WILLIAMS.

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