US2345749A - Gauge handle - Google Patents

Description

April 4, 1944. G. HOHWART 2,345,749

GAUGE HANDLE Filed Oct. 6, 1943 INV EN TOR. Geo/ e fl /z Wari.

Patented Apr. 4, 1944 2,345,149 GAUGE HANDLE George Hohwart, Orchard Lake, Mlch., assignor to N. A. Woodworth Company, Ferndale, Mich a corporation of Michigan Application October 6, 1943, Serial No. 505,112

4 Claims.

This invention relates to handles for plug gauges, thread gauges and the like, and has for its principal object the provision of a handle construction permitting the handle to be constructed mainly from plastic.

Objects of the invention include the provisions of a gauge handle for plug gauges or the like formed from molded plastic material and provided with a metallic insert therein for direct reception of the gauging element; the provision of a gauge handle as above described provided with a novel form of metallic insert; and the provision of a gauge handle as above described in which the metallic insert is of simple and novel character capable of being rigidly locked against movement in all directions to a plastic handle molded thereabout.

The above being among the objects of the present invention the same consists in certain novel details of construction and combinations of parts to be hereinafter described with reference to the accompanying drawing, and then claimed, having the above and other objects in view.

In the accompanying drawing which illustrates a suitable embodiment of the present invention and in which like numerals refer to like parts throughout the several differentviews,

Fig. 1 is a perspective view of a plug gauge provided with a handle formed in accordance with the present invention;

Fig. 2 is an enlarged fragmentary sectional view taken axially through the plug gauge shown in Fig. 1 as on the line 2-2 thereof;

Fig. 3 is a perspective view of the metallic sleeve or ferrule in the form it assumes before its inner end is flared and notched; and,

Fig. 4 is a view of the metallic insert or ferrule in its final form and ready to be molded within a plastic handle. 1

The word plastic as herein employed is intended to mean that class of materials which are thermal setting or thermal plastic and conventionally employed today in themolding of various articles of commerce and includingbut not limited to phenolic resins of the molding type, pheno-furfuralresins, urea. and melamine resins that are mixed with alpha-cellulose pulp, copolymerized vinyl chloride and vinyl acetate, vinylidene chloride resins, styrene resins, cellulose acetate, cellulose acetate butyrate, ethyl cellulose, lignin plastics, and the like.

It is conventional practice in making plug and thread gauges, and particularly those of the smaller sizes, to provide a metallic handle, commonly formed from hexagonal bar stock through which a central hole is bored, and which hole is outwardly flared at its ends for complementary reception and frictional engagement with the tapered shank of the gauging element, the taper of the shank and the bore being less than the angle and friction of the metal so that when the shank of the gauging element is firmly pressed into the flared bore at the end of the handle it is securely fixed and frictionally held to the handle. There are several reasons why it is desirable to find a substitute for the conventional metal handle of such gauges. One reason is because of a scarcity of steel at the present time. Another reason is that a metallic handle is usually cold to touch and, therefore, is not comfortable for a workman to'handle. In the larger sizes the handle becomes relatively heavy and, therefore, tiresome to a workman when continually employed. Accordingly, in accordance with the present invention the handle is formed mainly from a plastic of the type described and may be and is preferably formed to the same size and shape as a conventional metal handle.

In employing plastic for the handle of a gauge of the type described the characteristics of the plastic itself must be considered. Because it is relatively weak as compared to steel which is conventionally employed for such handles it is not possible to rely entirely upon the strength of the plastic material. In other words, if a handle is formed entirely from plastic the same as a oonventionalmetal handle, the tapered endof the plug when pressed into the handle wili, in many cases, radially expand the corresponding end of the handle to such an extent as to rupture it, and in any case such end will often rupture under the stresses to which it is subjected to in service.

It has heretofore been suggested to place a metal ferrule about the end of a plastic handle externally thereof but this construction is not satisfactory for the reason that under such conditions the plastic itself at such end is placed under compression when the gauge member is pressed into place. This difficulty is overcome in accordance with the present invention by inserting a ferrule or sleeve within the bore of the end of a plastic handle, the ferrule or sleeve being tapered so as to provide an interior surface complementary in size, shape and contour to the tapered shank on the gauge element and being so formed and constructed that when molded into the gauge handle it is securely. locked against movement in any direction relative thereto. This sleeve or ferrule directly receiving the shank of the gauging element absorbs the force of pushing the gauging element into place in the handle, thus relieving the plastic material itself from the effects of such force, and additionally reinforces the corresponding end of the handle against breakage in service.

It will, of course, be appreciated that the construction of the present invention is applicable to a gauge handle arranged to support a gauging element at one end only thereof, but inasmuch as it is conventional to form such handles to receive a gauging element at each end thereof this is the form of construction shown in the accompanying drawing by way of illustration. As illustrated in the drawing the handle which, of course, may be formed to any shape or contour in accordance with the broader aspects of the invention, is of the same hexagonal external shape as conventionally employed in conventional metal handles and is indicated generally at Hi. It is provided with a bore l2 in accordance with conventional practice. end thereof is received a metallic and preferably steel sleeve or ferrule ll of circular cross-sectional configuration over the main portion thereof and which flares outwardly from a point axially outwardly spaced from its inner end to the outer end thereof to provide a frusto-conical surface complementary in shape and contour to the tapered shank portion is of a gauging element l8 illustrated in the drawing as a conventional type of cylindrical 'plug gauge by way of illustration. The main body portion of the sleeve or ferrule i4 is circumferentially unbroken or unsplit. Iitwill be appreciated that the taper of the flared main body portion of the sleeve or ferrule i l will be 0.250 per foot in order to conform with the conventional taper of the shank iii of such gauging element.

The axially inner end portions or ferrules it are axially split as at 20 at a plurality of points around the circumference thereof, preferably at equally angularly spaced points about the axis of the sleeveor ferrule, and the portions of the sleeve or ferrule l4 intermediate the splits 20 are more or less flattened as indicated best in Fig. 4 and are bent outwardly away from the axis of the sleeve or ferrule l4 about their lines of connection with the main body portion thereof to form tab-like portions 22. particular case shown the inner end portions of the sleeves or ferrules l4 are split at six equally angularly spaced points and the intervening metal is bent out so that the inner end portions 22 of the sleeves or ferrules it present a hexagonal appearance in end view.

The outwardly .bent portions 22 are substantially completely imbedded in the plastic material of the main body portion of the handle so that the plastic, in being molded between the splits or notches 20, interlock with the sleeves or ferrules id to prevent any possible relative rotation between the sleeves or ferrules and the main body portion of the handle, and because the sleeves or ferrules it are reduced in diameter from their axially outer ends toward their axially inner end portions and the portions 22 flare outwardly from the latter ends the plastic material surrounding them thus eifectively locks them against axial movement.

The sleeves or ferrules M are, therefore, mechanically interlocked with the plastic material of the main body portion of the handle ill against of the sleeves Within the bore I2 at each Inthe ally, being formed for direct reception of the tapered shank l6 of the gauging elements l8 they aiford the same character of connection as is provided where such handles are made entirely from metal which has been proven satisfactory inasmuch as this form of connection has been used with metal handles for years. The radially expansive force exerted on the handle by forcing the tapered shank it of a gauging element i8 thereinto is, of course, taken directly by the corresponding sleeve or ferrule it thus relieving the plastic material itself from this force. At the same time because the ferrules or sleeves M are of a material length they serve to reinforce the corresponding ends of the handle against breakage due to the ,forces exerted thereon in service.

Preferably the sleeves or ferrules M are not made of the full length of the shank I6 on the gauging elements as it has been found that this is unecessary to obtain the desired amount of frictional lock between the shank I6 and the handle. Accordingly, and as best brought out in Fig. 2 the bore l2 of the main body portion of the handle i0 may be of such size axially inwardly of the sleeves or ferrules ll as to provide clearance between the bore and the portion of the shank it which projects axially inwardly beyond the sleeves or ferrules.

In making the sleeves or ferrules l4 they are first formed as frusto-conical members as illustrated in Fig. 3. Preferably a piece of metal tubing, and preferably steel tubing, of a diameter slightly less than that of -the smallest diameter desired in the completed sleeve is cut to length and a mandrel or die of the desired taper is forced thereinto to cause it to be expanded and conform thereto in taper to bring it to the form shown in Fig. 3. Thereafter a pointed punch (not shown) having as many sides as it is desired to have portions 22 in the final product, is forced into the smaller end of the sleeve in the form illustrated in Fig. 3 axially thereof, this causing the metal of the sleeve to split at the junction of said sides of the punch to form the splits 20 and simultaneously bending the portions between them outwardly to form the portions 22. It will thus be appreciated that the sleeves or ferrules H may be formed in a simple and economical manner. After being formed the sleeves or ferrules H are placed in proper position in the mold in accordance with conventional practice and the plastic material molded thereabout and to the shape shown in accordance with conventional practice thus resulting in the complete article.

The main body portion of the handle 10 may, of

7 course, be provided with the usual drift or knockboth axial and rotational movement. Addition- :5

out slots 24 therein to permit the introduction of adrift in order to drive the shank l6 of a gauging element i8 out of the handle where it is desired to remove it for replacement or for other reasons. Although two such slots 24 are shown, and which is satisfactory, it will be appreciated that one only may be provided to permit one of the gauging elements only to be removed by a drift introduced therethrough, upon the removal of which a rod may be projected through the handle to remove the remaining gauging element if desired.

It will be appreciated that the final article will be considerably lighter than an equivalent handle formed from metal and particularly from steel and, therefore, less tiresome to use, that because of the fact that plastic is a good heat insulator it will not feel cold to the hand of the workman as in the case of a metal handle, and that is relatively inexpensive to manufacture.

Having thus described my invention, what I claim by letters Patent is:

l. A handle structure for a plug gauge or the like comprising a hollow main body portion of plastic material and an outwardly flared metal sleeve received and exposed in said bore at one end of said main body portion, and outwardly directly circumferentially interrupted portions integral with the inner end of said sleeve imbedded in and surrounded by the plastic material of said main body portion.

2. A gauge handle comprising a metal sleeve of circular cross-sectional configuration and frustoconical conformation, radially outwardly bent and circumferentially separated tabs integral with the small end of said sleeve, and a plastic body surrounding said sleeve and imbedding said tabs therein, said body having a bore in which the tapered inner surface of said sleeve is exposed, said bore extending axially inwardly of the inner end 01' said sleeve.

3. A gauge handle comprising, in combination, a hollow main body portion formed from plastic, a circularly sectioned axiall'y tapered circumferentially unbroken metal sleeve received within the bore of said handle at each end thereof, and a plurality of circumferentially separated relatively flat tab portions integral with the inner end of each of said sleeves bent radially outwardly with respect to their lines of junction with the corresponding of said sleeves and imbedded in the material of said main body portion.

4. A gauge handle comprising, in combination, a hollow main body portion formed from plastic, 8. circularly sectioned axially tapered circumferentially unbroken metal sleeve received within the bore of said handle at each end thereof, and a plurality of portions integral with the axially inner nd of each of said sleeves arranged in angularly spaced relation about the axis of said 20 sleeve and flared outwardly with respect to the axes of said sleeves, said portions being flattened whereby to present a polygonal shape to the corresponding ends of said sleeves in axial view.

GEORGE HOHWART.

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