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Publication numberUS913677 A
Publication typeGrant
Publication dateMar 2, 1909
Filing dateAug 10, 1908
Priority dateAug 10, 1908
Publication numberUS 913677 A, US 913677A, US-A-913677, US913677 A, US913677A
InventorsGeorge M Ainsworth
Original AssigneeGeorge M Ainsworth
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
US 913677 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)




Patented Mar. 2, 1909.

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Specification of Letters Patent.

Patented March 2, 1909.

Application filed August 10, 1908. Serial No. 447,732.

To all 'whom tt may concern:

Be it known that I, GEORGE M. AINs- WORTH, a citizen of the United States, residing at Cedar Rapids, in the county of Linn and State of Iowa, have invented certain new and useful Im rovements in Center-Punches, of which the ollowing is a specification.

yMy invention relates to center punches, and the object of my invention is to provide a center punch rovided with a hammer which may be raised) by a single movement of the fin er and then automatically released.

further object of my invention is to provide a device as mentioned in which the hammer ma be raised to the extent necessary to give a b ow ofthe desired force, and then automatically released.

A further object of my invention is to provide a center punch characterized as mentioned which shall not be injured by operating the hammer when not in use, and one which shall be of simple construction and of low cost of manufacture.

Other objects will appear hereinafter.

My invention will be more readily under'- stood by reference to the accompanying drawings, forming a part of this speciiication and in which,

Figure 1, is a side elevation of a center unch embodying my invention in its preerred form, the parts being in the position they assume after the hammer is released, Fig. 2, is a section of the punch illustrating the hammer partially raised and Fig. 3, is a section on the line x-as of Fig. 2.

Referring to the drawings, 1 indicates the body portion of the device. This comrises a hollow cylindrical member which is urled or roughened upon its outer face, as at 2, forming a handle or grip portion. The knurled portion 2 may be co-eXtensive with the outer surface of the member 1, but l prefer to have the same arranged toward or at the lower end only where it is engaged by the three outer ngers of the hand holding the same, the forefmger of the same hand being used to actuate the hammer as hereinafter described. By providing the upper portion of the member 1 with a smooth surface 3, the device may be more comfortably operated, as the fore or operating finger, the thumb and the ortion of the hand between the operating iinger and said thumb will not become chafed by rubbing against a roughened surface. Also byproviding the roughened portion or grip atthe lower end, the operator will be led to grasp this portion which places the device in the best position for readily and easily actuating the hammer.

The body 1 is provided With a cylindrical bore 4 terminating near the lower end in a dished or conical shoulder 5 and a reduced and co-axial bore 6. Upon the lower end of the body portion, is the tool or punch roper 7, having a stem 8 extending into the ore 6. The punch is provided with a shoulder 9, between the portions 7 and 8 which rests against the preferably reduced lower end 10 of the portion 1 when the punch is pressed against the work, designated at a in Fig. 1. The shoulder 9 is preferably formed by the upper face of an annular flared collar 11 formed integrally with the punch. The stem 8 is somewhat longer than the bore 6 in order that its up er end shall extend above the face of the s voulder 5 and into the path of the hammer, when in o erative position. To revent injury to t e punc by operating t e hammer when not in use, the stem 8 of the punch is slidably mounted in the bore so that its upper end will drop below the shoulder 5 except when the punch is held against the work,v at which times said shoulder serves as a stop for the hammer.

13 indicates the hammer, which is arranged within the bore 4 and is of but slightly less diameter than the same. The hammer is rovided with longitudinal grooves 14 W 'ch are of sufficient size to prevent compression of air beneath the hammer which would lessen the force of the blow. The upper end of the body 1 is closed by a head 15 having a depending portion 16 threaded into the upper end of the bore 4 forming a `plug, between which and the upper end of the hammer, is arranged a s ring 17. When the hammer is raised and tien released the spring drives the same forcibly against the upper end 12 ofthe stem of the punch, or against the shoulder 5 as the case may be. It should be noted that the lower end of the hammer is shaped as at 18 to conform to the shoulder 5, that is, the hammer is provided with an inverted frusto-conical lower end.

The hammer is provided with a stem 19 which is quite long and extends through a bore 2O in the head 15 and a considerable distance above said head, forming a guidewayfor the hammer raising device. The hammer raising device comprises a sleeve 21 slidably mounted on the upper or projecting end of the stem Y19 'and-'havinga device for` engaging said stem to raise thesameas said sleeve 1s raised and an actuating lever 22 surface, and ears 23 preferably project from the periphery thereof. The inner or work end of the lever is bifurcated forming the two armsz24-24' upon each sideI of the stem.Y 1.9, which are. connected by links: 25 to the sleeve 21. anl upper andl lower collar or rib 26-27 re spectively7 and the upper ends of the links 25are ivotally connected to.y the. up er rib 26; Tige links25 are of such length lt at the arms 24 of the lever rest upon the upper face of thehead 15 whenthe sleeve 21 is in lowermost. position. The'lower end of thesleeve, andi: upon the sidei adjacent tothe lever is horizontally slotted as at 28,V saidY sloty extending through` the ribbed.' portion 27 and into the bore 21;Va of: the sleeve.

to engage notches 30,v 31 and 32 formed'. in the= stem 19=f abovethe head 15. The inner edge ofvg the pawl 29 is curved as at 33: to conform tof they stem 19. The edgev 33 is beveled: asishownin'Fig'. 2, and thewalls of" the annularnotches or'grooves.V 30, 31 and: 32

are correspondingly inclined forming the.

ratchet connection between the. sleeve and the stem, permitting free downward` movement of theV sleeve but which' prevents the samev from rising without alsor raising the stemfandl the hammer.Y Fixed toftherib 26 is aspring 34;- which bears against the pawll 29, .itslower' end resting in a notch 35-formed in the pawl.

The lever 22,` after itl passes the pivot pointl 23?, is bent downwardly forming a shoulder 36V and then outwardly terminating inan eye or ring;37 to receive the forefinger ofthe handholding thetool. It is obvious that bydrawing downon the-lever the'sleeve 211willbe.raisedf, andthe ratchet having engaged the stem, the hammer will be raised..

Theupward` movement ofthe sleeve is limited by theshoulder 36of the lever engaging.

tlie'bo'dy l: ofthe tool.

As. the sleeve-2:1 approaches theupward The. body of thert'ool is graspedin: the hand with: the forefinger extended through the ring 37- and thev point'y 7" is. pressed firmly against the workc at the desired point. The

leveri 22.' is then raised by the `:forefinger until the? pawl 29.. engages one. ofY theA annularv The sleeve 21 is provided with Mounted in the; slot 28' is a pawl 29 which is adapted' notches3l, 317er 32. The lever u22V isthen drawn down vby the forefinger, raising the hammer againstl the tension of the spring 17 As the-.sleeve 21 approaches the u permost position the links 25 swing inward y almost to a vertical position and by engaging the extensions 38 of the pawl moves said pawl 'out off engagementv with the notched stem.

The spring 17 then drives the hammer forcibly against the upper end l-2 of thepunch stem. The force off the blow may be' regulated by engagingA the pawl: 29 with one or the other ofthe notches 30, 31 or 32. It shouldbe noted that the pawl is released. at the'same point ineither casebut that' by en gaging the pawll with the'notehi13()I thelliam mer is raisedv butV a: comparatively short distance, whereas by engaging thefnotclr'r3'1f it is raised a greater distance, andwhenl the notch; 32 is used it is raised tolth'egreatestv height, the blow of the'hammer increasing accordingly. To prevent-separation of the punch toolfromv thel handle or bodyv portion, the

stem 8 is notched or recessed atA 39=ahd=a pin 40 is threaded throughthe reduced end?l 1:()fofV the body portion and extends intosaid-fnotch. The notch'39 is of sufficient length toifpermit the end 12 of` the stem toV shoulder 'whenfnot inuse;

Having described my' inventionywhat Ir pass Ybelow the,

claim as new and desireto secure'by Letters Y Patent is: Y

1. A center punch'comprisingiabody portionzformingafhandlefand apunch at oneend thereof, inl combinationr'withl a'- spring'.` actuatedI hammer arranged' withinl said handle, a stem on said hammer projectingtthroughr the end of" said handle opposit'e froml said punch, aVV lever pivotally mounted onthe end of said handle adjacent tolthe rojectingiendf of :saidV stem for raising saidi ammer, said lever beingv shaped toform astop to: engage the side of said-handle to limit the rmovementv of the lever and av rin on the end' of said lever, substantially as escribed.

2. A center punchV com risingfavbody'portion-forming a handle'an 'apunch arranged atA one endthereof, in: combinationtherewith a hammer arrangedrwithin: saidbody portion g a stem on: saidn hammer extending throughY the opposite end of7 said body from sai'df` punch, asleeveslidably mounted onthe projectingf end of said stem,.means operablev by a fingerv of they hand grasping) theA tool for raising and loweringv said'-` sleeve, af ratchet.

connectionbetween said sleeve and saidf stem, and means. for brealxmgsaid connection as said'sleeve. reaches uppermost position; subLv arrangediwithin saidl handle, a spring int-er`V- posed between said hammer and said head, a

stem on said hammer extending through said head and rojecting beyond the same, a sleeve slida ly mounted on the projecting end of said stem, a ratchet vconnection between said sleeve and said stem, a lever for raising and lowering said sleeve, a link connecting said lever and said sleeve said link being adapted to break said ratchet connection when the sleeve reaches u permost position, substantially as described.

4. A center punch comprising a tubular body portion forming a handle, said body portion being o en at the top, in combination with a unc tool arranged at the opposite end, a p ug threaded into said open end and having a central bore, a hammer arranged Wit in said handle and having a stem extending through said bore, a s ring interposed between said hammer an said plug, an operating lever pivotally mounted on said plug and a suitable connection between said ever and said stem, substantially as described.

In testimony whereof I have signed my name to this specification in the presence of subscribing Witnesses.




Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2451217 *Apr 6, 1945Oct 12, 1948Auto Diesel Piston Ring CompanShock absorbing hammer
US2455577 *Apr 5, 1945Dec 7, 1948Hager Emil FCenter punch
US2460113 *Dec 6, 1946Jan 25, 1949Geoffrey Young SidneyCentering or like punch
US2470891 *Mar 18, 1947May 24, 1949Hammers IncSpeed nut tool
US2576704 *Mar 19, 1949Nov 27, 1951Seneca Falls Machine CoMeans for engaging and driving rotated workpieces
US2607149 *Feb 3, 1950Aug 19, 1952Cox Edwin PDevice for disengaging fischhooks or the like
US2762435 *Mar 12, 1954Sep 11, 1956Morris Marie ACenter punch
US2783670 *Aug 16, 1955Mar 5, 1957William T NeimanImpact tool
US2903932 *Jun 27, 1957Sep 15, 1959Patrick A McgonagillAxial impact type hand tool
US3494431 *Oct 9, 1968Feb 10, 1970Harrison P RandolphSheet material punch gun
US3900058 *Sep 12, 1974Aug 19, 1975Mcardle MeadeMultipurpose impact hand tool
US20030089755 *Feb 19, 2002May 15, 2003Peers-Smith Roy PeterDevice for breaking glass
US20060255084 *Dec 13, 2005Nov 16, 2006Roy Peter Peers-Smith; Anthony Graham Partington; Martin LawranceDevice for breaking glass
DE102004025036A1 *May 18, 2004Dec 15, 2005Andreas GrosseAutomatic-punching grain measuring device for electronic positioning has optical sensor arranged inside guide sleeve to pass material measurement results to control unit
Cooperative ClassificationY10S81/12, B25D5/00