US783749A - Center-punch. - Google Patents

Description

Nea/"1783.749

PATBNTED FEB. 28, 1905. J'. J. HARTLEY @c J. M. STRYHAL.

CENTER PUNCH. APPLIUATIGN FILED APR. 26, 1904.

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diran STATES Patented February 28, 1905.

ATENT Ormea.

.hit/IES J. HARTLEY AND JOSEPH- M. SiRYH'AL, OF SCHEN ECTADY, NFA/V YORK, ASSIGNORS T0 BROWN & Sl-IARPE MANUFAClURlNG- CO., OF

IRUVIDENUE, RHODE ISLAND.

SPECIFICATION forming part of Letters Patent No, 783,749, dated February 28, 1905.

Application tiled April 26, 1904. Serial No. 204.970.

Be it known that we, Janus J. HAR'rLnY and .losnrn M. STRYHAL, citizens oi' the United States, residing' at Schenectady, ,in the county of Schenectady and State of New York, have invented a new and useful Improvement in Center-Punches, of which the following` is a speciiication.

This invention relates to improvements in punches, and refers more particularly to a centering' and prick punch `for machinists use in makingl suitable indentations in metal preparatory to drilling' the same.

The object oi' this device is to produce a neat and compact tool for the purpose mentioned in which all ot' the elements necessary to produce the desired indentation are conlined within a suitable handle or case and brought into action automatically by the mere pressure or the prick-point upon the article to be indented.`

Anotlier object of the invention is to produce a center -punch operated by a springiiiressure to indent the metal without the use oi' a hammer or other independent driving` device, whereby the indentation `forming the center may be accurately located and impressed on the metal without any radial or lateral strain exerted on the punch.

Further objects will appear in the subsequent description.

ln the drawings, Figure l is an elevation oi" a tool embodying our invention. Figs. 2, 3, and 4 are vertical sectional views through the device seen in Fig'. l, showing' the operation and manner o't applying the same, the parts being' normal in Fig'. 2 and partially compressed in Fig'. 3 and the striker-plunger as operated in Fig'. 4 to produce the desired indentation. Figs. 5, 6, 7, 8, and 9 are detail views of the detached parts ot' our invention.

Similar reference characters indicate corresponding' parts in all the views.

Yln carrying' out the objects stated we provide a suitable case, which not only serves to inclose and guide the movable parts hereinafter described, but also forms a handle by which these parts may be brought into action.

rlhis case is shown as consistin, 1;o'tl a slightlytapering' tubular body 1, having a tubular tip or guide 2, secured to the lower part of the concentric tubular body, while the Lipper part is normally closed by a cap 3, also secured to the main body l. A punch-rod 4 is reciproeally movable in the lower end of the case and extends above and beneath the opposite ends ot the section 2, in which it is guided, the lower extremity being' tapered to a sharp point 5, which lies in the axis ot the punchrod and tubular bodyl and serves to produce the desired indentation in a manner hereinafter described. The upper end of this punchrod 4 is provided with an enlarged head 6, which is guided in a cylindrical chamber 7 in the lower end of the tubular body l. lhe upper end of the tubular section 2 is provided with a bushing' 8, which encircles the punchrod 4 and forms an additional guide 'for the said rod in its reciprocal movement, the bushing' being usually screwed into the upper end o't' the section Q, which latter is drawn in toform a guide for the lower end ot' the punchrod. This rod 4 is provided with laterally-projectingl shoulders 9, located between the bushingl 8 and an annular shoulder l0 at the base of the section 2, and between the shoulders El and bushing' 8 and encircling' therod 4 is a coil-spring' l1, which operates to lorce the punch-rod 4 f ,lownwardly, so that the shoulders 9 normally rest upon the shoulders l0, as seen in Fig. 2.

The head 6 of the punch-rod 4 is provided with a recess l2, Fig'. 9, in which is inserted one end ot' an upright pawl 1,3, rising' from the head 6, the lower end o't' the pawl, which enters the recess, being reduced in width, so as to form lower and upper shoulders on the pawl which engage the opposite faces of the head 6 to hold the pawl from endwise displacement and at the same time to permit the pawl to be moved positively endwise by the movement oi" the punch-rod 4, it being' understood that although the pawl 13 is removable laterally Jfrom engagement with the head when the parts seen in Fig'. 9 are detached Afrom the main body l said pawl is held in its upright position from lateral displacement by the adjacent side wall of the central body 1 when the parts are assembled.

A plunger' or striker 14 is reciprocally movable in the upper end of the main body 1 and consists of a cylindrical body, of iron or equivalent material, having a lengthwise groove 15 in one of its upright faces for receiving a tripping' member 16, said g'roove being extended upwardly from the lower face of the plunger or striker 14 and is also adapted to receive the upper end of the pawl 13 when it is tripped'. rlhis pawl 13 is provided with a tooth 17, which normally engages the lower face of the plunger or striker 14, which is undercut to form an engaging' tooth, and the pawl is held in this position by a spring 18, said pawl being' adapted to elevate the plunger or striker 14 against the action of a spring 19 when the point is engaged with the article to be indented and when the handle or case is depressed. The spring' 19 is arranged within the case and is interposed between the cap 3 and upper end of the plunger or striker 14,

so that when the plunger or striker is elevated against the action of the spring' in the act of making' an indentation in the article the trip 16 automatically releases the tooth 17 of the pawl 13 from engagement with the plunger or striker and the spring 19 instantly operates the plunger or striker downwardly with considerable force against the upper end of the punch-rod 4, thereby producing the desired indentation, which indentation may be deepened by repeating' the operations just described, and the tension of the spring 19 may be varied by adjusting the cap 3.

The tripping member 16 is removably secured to the tubular body and is held in place by a stud or pin 20, which enters an aperture 21 in the side wall of the inclosing' case, said stud being secured to the tripping-member and is simply inserted in the aperture to hold the member from endwise movement, it being' held from lateral movement by the plunger or striker and adjacent wall of the case, between which parts the said member is located.

In the operation of our invention the point 5 is tirst located at the desired point upon the article to be indented, whereupon the device is brought to an upright position and the operator engages the case or handle and depresses the same, first against the action of the spring 11 and then against the action of the spring 19, it being understood that during this depression of the case the tooth 17, which normally engages the lower edge of the plunger or striker, elevates said plunger or striker a limited distance until the upper end of the pawl,which projects slightly beyond the tooth 17, eng'ag'es a cam-face 22 upon the lower end of the tripping member,whereupon the plunger is released and the spring' 19 forces the plunger downwardly with considerable force against the upper end of the punch-rod 4, and

thereby produces the desired indentation. The tooth 17 is located some distance above the upper end of the punch-rod 4, and therefore permits the plunger to be moved through such distance by the action of the spring 19 before striking the upper end of the punch-rod. It is thus apparent that two forces are applied to make the indentation, one by the pressure of the operator upon the case or handle and the other by the instantaneous blow produced by the plunger 14 and spring' 19.

The central tubular body 1 is provided with an inner annular shoulder 23, which serves to limit the downward movement of the plunger, the shoulder 23 and the shoulder 17 of the pawl 13 being' so relatively arranged that when the plunger is seated on the shoulder 23 the shoulder 17 is in position to engage the plunger when the punch-rod is elevated or, more properly, when the handle or case is depressed.

vHaving thus described our invention, we claim as new and desire to secure by Letters Patent4 In a center-punch, comprising a tubular body having' a threaded upper end, and a cap screwed on said threaded end, a tip removably secured to the lower end of said body,aspring pressed punch-rod in said tip, a head on said rod extending into said body, said head being recessed with an upright pawl entering' said recess at its lower end, the upper end of the pawl bearing against the interior of the body, a solid plunger of the same cross section throughout'arranged in the body, a spring' seating directly upon the upper end of said plunger and bearing against the interior of the cap. said cap being concaved on its under face to form a seat for the spring' to retain the latter in position, said plunger having' a lengthwise groove formed therein, a trip member arranged in said groove, said trip member formed of an elongated strip of material having' its lower end curved inwardly to bear against the bottom wall formed by the plunger-g'roove, said threaded portion of the body adjacent its lower end being formed with an aperture, a rivet extending through said aperture and secured to the upper end of said trip member, said plunger-groove receiving the Lipper' end of the said pawl when the latter is tripped, said inwardly-curved lower end of the trip member forming a cam-face on its outer face, said pawl having' an inwardly-extending' shoulder normally engaging' the said plunger and retaining the latter in its upright position.

ln testimony whereof we have signed our names to this specification in the presence of two subscribing' witnesses.

JAMES J. HARTLEY. JOSEPH M. S"RYHAL.

lfitnesses:

ALEX. F. MACDONALD, GnNnvinvn HAYNns.

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