US437308A - Edward r - Google Patents

Description

(No Model.)

E. R. MARKHAM. SURPAGE GAGE.

Patented Sept. '30. 1890.

FIG. 2.

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WITNESSES:

93am Q By his A omeys, m. 6204 m C UNITED STATES PATENT OFFICE.

EDXVARD R. MARKHAM, OF OHIO OPEE FALLS, MASSACHUSETTS, ASSIGNOR TO THE J. STEVENS ARMS AND TOOL COMPANY, OF SAME PLACE.

SURFACE-GAG E.

SPECIFICATION forming part of Letters Patent No. 37,308, dated September 30, 1890.

Application filed April 7,1890- Serial No. 346,866. (No model.)

To all whom it may concern.-

Be it known that I, EDWARD R. MARKHAM, a citizen of the United States, residing in Ohicopee Falls, Hampden county, Massachusetts, have invented certain new and useful Improvements in Surface-Gages, of which the following is a specification.

Surface-gages are ordinarily constructed with abase and an upright post projecting therefrom, to which the pointer is fastened at any desired height-through the medium of a sliding clamping-sleeve. The adjustment of the pointer is commonly effected by setting the sleeve at any convenient height and then turning the pointer on its swivel until its point is brought into contact with the surface to be tested, whereupon the clamping-screw is tightened to fix the pointer in position. To facilitate the accurate adjustment of the pointer, surface gages have been made wherein the post is bodily adjustable up or down relatively to the base by means of a screw at the base.

My invention is an improvement upon surface-gages of this class, its object being to improve the accuracy and stability of the instrument, to bring the adjusting-screw into more convenient position, and to enable the screw to be constructed with graduations to be read to fractions of an inch or other minute measurement after the manner of a micrometer-screw.

According to my invention the post is made tubular or as a sleeve and is mounted on a guiding-rod projecting up through it, which rod is fastened fixedly to the base, the tubular sleeve being pressed upwardly by a spring against a screw or nut engaging the rod, and by turning which the sleeve is caused to move up or down. A pin and slot are provided to prevent the rotation of the sleeve.

Figure 1 of the accompanying drawings shows the preferred form of my improved surface-gage in side elevation. Fig. 2 is a vertical transverse section thereof. Fig. 3 is a similar section of a slightly-modified construction. I

LetA designate the base; B, the upright post mounted thereon; O, the pointer, and D, the clamping-sleeve, by which the pointer is fastened to the post. The pointer is mounted as usual by being passed through a clampingsocket in a divided swivel-head E, the shank e of which constitutes a screw-threaded rod passing through the ears cl of the divided sleeve D with a thumb-nut F screwed on its protruding end, so that by tightening this nut not only is the sleeve D contracted and made to tightly embrace the post B, but the swivelhead E is clamped tightly in position, so that it cannot turn or oscillate relatively to the sleeve D, and its two halves orj aws are pressed together so that they embrace the pointer-rod tightly between them and prevent the longitudinal movement of the pointer through the head. This is a usual means of attachment employed with surface-gages.

That which is characteristic of my invention is the construction of the post B as a tubular sleeve adjustable up or down by sliding over an internal guiding-rod H, which is fixed to the base A, and the construction of the adjusting-screw as a micrometer-screw, and its arrangement at the top of the post. The ad justing-screw has a milled head G, or other be adjusted with the greatest nicety and exactness to the proper position.

The preferred construction is best shown in Fig. 2. The vertical guiding-rod H is fixed rigidly at its lower end to the base A, as clearly shown, and projects only partly through the tubular post or sleeve B. The adj usting-screw J enters the sleeve from above and its lower end screws into a threaded socket formed in the upper part of the rod H. The shoulder j of the adjusting-screw, on which the head G 0 is formed, rests upon the upper end b of the sleeve and limits the upward movement thereof. The sleeve is kept pressed firmly upward against this shoulder by a spring S, arranged in the annular space between the screw-rod J and the sleeve, its lower end reacting against the top of the rod H and its upper end pressing upwardly against an inturned flange or shoulder at the upper end of the sleeve, this shoulder being preferably formed in a thim- 10o ble (shown at b) screwed or otherwise fastened to the upper end of the sleeve to form the top or head of the tubular post. To prevent turning of the post it is formed at the lower part of the sleeve with a slot a, engaged by a pin 0, projecting from the rod II.

In order to facilitate the making of minute adjustments, the shoulder j is marked with micrometer-gradnations, which can be read with reference to a mark f on the head I) of the sleeve. These graduations may represent fractions of an inch or other minute measurement.

In the construction shown in Fig. 3 the guiding-rod II projects up entirely through and above the top of the tubular post or sleeve B, and the adjustin -screw is in the form of a nut J, screwing on the threaded upper end of this red. The shoulder or neck of this nut may be graduated after the manner of micrometer screws, to the same effect as shown in Fig. 1. The spring S is applied beneath the sleeve B, resting against the bottom of the recess in the base A, and pressing upwardly against the bot-tom end of the sleeve. Rotation of the latter is prevented by slots a and pins 0.

The vertically-adjustable sleeve and its internal guiding-rod H may be mounted and relatively arranged in numerous other ways and provided with other means for propelling the sleeve up or down. It is notessential that the sleeve be pressed by aspring against the adj Listing-screw, although this construc tion is preferable,because it takes up any lost motion which might otherwise give rise to inaccuracy in the adjustment. Such lost motion might arise by looseness in the screwthreads in case the adj usting-screw were employed without any spring to propel the post in both directions.

By my construction the adj Listing-screw is brought to the top of the post instead of being at the base, as heretofore, which renders it much more convenient of access and enables its graduations to be readily seen, so that to impart any given desired movement to the pointer the screw can easily be turned to exactly the necessary extent by aid of the grad nations. By my improved construction of the post so that it is guided interiorly by a rigid rod projecting up within it a considerable distance, (or even entirely through it, if desired,) it has an extended bearing-s11 rface for guiding it, so that it is more strongly and accurately supported and guided than heretofore.

I claim as my invention the following defined novel features, substantially as hereinbefore specified, namely- 1. In a surfacegage, the combinatiomwith the base, of the upright post constructed to be adjustable vertically relatively to the base, aspring tending to move it in one direction, and a screw for adjusting it arranged to move it in the other direction against the tension of said spring.

2. In a surfaeegage, the combination, with the base, of an upright tubularpost or sleeve, a guiding-rod within said post and fixed to the base,a spring arranged to press the tubular post upwardly and an adjusting-screw for forcing it downwardly.

In a surface-gage, the combinatiomwith the base, of an upright tubular post or sleeve, a guiding-rod fixed to the base and projecting part way within the tubular post, and an adjusting-screw consisting of a screw-rod entering the upper part of the post and screwing into said guiding-rod and having a head above the post engaging the top thereof.

4. I11 a surface-gage, the combination, with the base, of an upright tubular post or sleeve, a guiding-rod fixed to the base and projecting part way within the tubular post, and an adj listing-screw consistin of a screw-rod enterin g the upper part of the post and screwing into said guiding-rod and having a head above the post bearing against the top thereof, and a spring arranged to press the tubular post upwardly against the said head.

In witness whereof I have hereunto signed my name in the presence of two subscribing witnesses.

EDXVARD R. MARKHAM.

\Vitnesses:

JAMES H. Looms, FRED W. SMITH.

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