US1537628A - Tool holding and driving mechanism - Google Patents

Tool holding and driving mechanism Download PDF

Info

Publication number
US1537628A
US1537628A US597713A US59771322A US1537628A US 1537628 A US1537628 A US 1537628A US 597713 A US597713 A US 597713A US 59771322 A US59771322 A US 59771322A US 1537628 A US1537628 A US 1537628A
Authority
US
United States
Prior art keywords
driving
tool
rollers
rotation
holding
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US597713A
Inventor
James A Street
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
HUGO C ZEITZ
Original Assignee
HUGO C ZEITZ
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by HUGO C ZEITZ filed Critical HUGO C ZEITZ
Priority to US597713A priority Critical patent/US1537628A/en
Application granted granted Critical
Publication of US1537628A publication Critical patent/US1537628A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B23MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23GTHREAD CUTTING; WORKING OF SCREWS, BOLT HEADS, OR NUTS, IN CONJUNCTION THEREWITH
    • B23G1/00Thread cutting; Automatic machines specially designed therefor
    • B23G1/44Equipment or accessories specially designed for machines or devices for thread cutting
    • B23G1/46Equipment or accessories specially designed for machines or devices for thread cutting for holding the threading tools
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T408/00Cutting by use of rotating axially moving tool
    • Y10T408/70Tool or tool-support with torque-applying clutch
    • Y10T408/72Friction clutch

Definitions

  • My invention relatesy to improved toolholding and driving mechanism of simple, sturdy construction.
  • An. object is to provide in'iproved tool-holding and driving mechanism of simple, sturdy, efficient design which is so constructed that in tapping, drilling, bolting, studsetting or other'operations the tool-holding portion. of the mechanismI may be released from. the driving power when the imposition of resistance t0 the rotation oft the tool approaches the danger point.
  • lvy invention con'iprises anA improved construction which permits: release olf the tool troni. the driving iorce upon. dangerous increase of resistance torotation and continued. overrunning by the driving member of the driven tool-holding member during,
  • Fig. 2v is a verticalfsection through the barrel portion of the chock taken on .line HMH; of Fig. 2.
  • Fig. 3 ⁇ is a cross-sectional view taken on the line III-III of Fig. 2.
  • Fig. 4 is a cross-sectional view taken on the line TLV-lV, of Fig. 2.
  • Fig. 5 is a perspective of one of the cam levers 42. f f
  • Fig. 6 is a perspective of one of the vertically movable camsit-(i.
  • Fig. is a broken away vertical sectional view through the barrel.
  • Fig. 8 is a sectional: Viewl taken onl the same line as Fig. 3 showing the tool-holding' member and driving member ⁇ coupledy together ttor driving.
  • v V v l F ig. 9 is a ⁇ sectional view taken on the line 9?-9 of Figz. v
  • Fig. l0. is a ⁇ verticaly sectional view'taken on thev line l0-10 ofFig. 1l.
  • Fig. l1 is a. horizontal*sectional view through a modiliedformof my deviceftaken on the same line as Fig, B. l y
  • My improved. tool ⁇ comprisesy a, drivingv niembe and a driven?tool-holding member adapted, to be releasably coupled withy said driving. memberv to. rotateA therewith but which coupling islet such a character as to permit said; driving member to. rotate independently, of the tool-holding member when v the rotationol" the tool is obstructed tosuch a. degree as to approach the danger point ot' breakage thereof.
  • I y provide ⁇ spiral springs -27 and 28,v which, however,v i are, yas will be seen, yieldable to permit pivvota'l movement ofthe toolsoclret'so that the tool may be ydriven though it is not alined 4axially with the driving member'.
  • the head 2l of the driving member is diav metrically recessed as at 29, which diametri-l cal recess is provided with an axial recess 30. l provide adriving head 3l having a diametrically arranged portion 32 which is disposed within the diametrical recess 29 in.
  • the head 2l and the* portion is provided -with a stein 33 receivable within the recess 30 in the head 2l.
  • a spring 34 Surrounding Athe stem A.is a spring 34 which exerts downward pressure Aon thedriving head 3l.
  • a hearing plate 35 Positioned in the bottom of the barrel is a hearing plate 35, which Iis shown as locked I to depend below the lower facevof the drivhead. These rollers are adapted to enl .zo
  • this vrecess 39 are two slidably disposed' 'blocks 40 held outwardly therein by means liaco ot the bearing plate gage in opposite endsof a diametrical recess 39 ⁇ fo'rmed in theibeari'ng plate 35 to pro-v cute rotation of .the bearing plate as one piece with the driving vhea-d 3l.
  • Mounted in of a spiral vspring 41,..the upper surfaces of which blocks lie flush withthe upper sur- Pivoted to l' each block is a cam lever 42 which. is secured to v'the bearing plate by means of a vertical v lever.
  • the driving head 3l carries in addition to the rollers'37 a pair of vertically movable Acammembers 46 shown ⁇ in perspective in Fig. 6. These cams are disposed in verticalv openings extending through the driving "head which are shaped to receive thev cam and each cam is providedwith 'a flange' 47 which rests upon the upper surface of thel driving head. Each cam isheld downwardly by means of a spring 48, one end of which engages the lower end of the head 21 and the other end of the spring is received over a stud 49 formed on the upper end of the cam46. The cams are narrowed to anedge at one end as at 50 and-the opposite end of the cam is beveled as at 5l.
  • Figs.r l0, 11 and 12 I have shownA a modified ⁇ form of construction in that in stead ofthe cams 46 engaging the two levers 42, these cams engage a single slidable block beveled as shown in Fig. l2, which block is provided with a baseplate 5l disposed lwithin a radial recess formed in the bearing.
  • levers are pivoted to the blocks 40 ask heretofore setl forth butv project loutwardly' in a different fashion so thatfeach lever is acted upon by the block .50 at the same time and inward Y* movement of the block ⁇ 50 spreads'the-outer ends of the levers apart andpbrings .the inner ends togetherwithdrawing the blocks 40 against the tension of the spring 4l to permit .the rollers to engage in the recess 39.
  • a device ot the class described, in conibination, a. driving member, a driven tool-holding; member, rollers carried'by one member held under spring* pressure to engage said other member to cause said members to rotate as one piece. and releasable to permit independent overrunningrotation ot said driven member by said driving mem- ⁇ beil upon imposition of resistance to rotation upon said driven member sullicient to overcome the spring pressure' ⁇ on said rollers, and means operable to prevent reen gagement of said rollers during said over'- running' rotation.
  • depressions and means operable to preo.
  • a'driving member, -a 'driven' vent re.-'engagement ot said rollers in said depressions yduring the continuance oit rotation ot' said driving member.
  • a driving member a ldriven tool-holding member, rollers carried by one of ,said members, a 'bearing plate for ⁇ said rollers carried by ksaid other member provided With depressions Within 'which said rollers may engage to couple said members together to rotate as one piece inthe forivard direction, spring means holding said rollers under pressure to engage in said -depressions, spring-controlled vmeans operable to prevent re-engagement ot said rollers in il said depressions during the continued toi'- Wai'd rotation of said driving member.
  • a device of theclass described in combination, a drivingr ⁇ member, a driven tool-holding member,,rollerscarried by one ot' said members, a bearing plate 'tor said rollers carried by said other member provided Witli depressions Within which said rollers ⁇ may engage to couple said members togetl'ier to rotate as one piece in the 'tor- Ward direction, spring means holdingl said rollers under pressure to engagel in said depressions, spring-controlled means operable to prevent i'e.engageinent ot said rollers in said depressions during' the continued torivard rotation ot said dri-ving membeivre-v leasable 'to permit such yre-'engagement upon vreversal of rotation ot said 'driving member.

Description

May 12, 1925.
' 1,537,628 J. A. STREET TOOL HOLDING AND DRIVING MECHANISM IFiled oct. so, 1922 2 sheets-sheet 1 May 12,1925. A f i 1,537,628
' J. A. STREET TOOL HOING AND DRIVING MECHANISM i Filed Oct. 30, 1922 2 Sheets-Sheet 2 @Gimmy Patented May l2, l925.
UNITE. ,STATES J'AhES A.. STREET, `OFl DETROIT,
PATENT oFFifc-s.
MICHIGAN, ASSIGNQR GF ONE-HALF 'lO HUGO C.y
ZEITZ, 0F CLA-RKS'BURG, WEST VIRGINIA., n
TOOL HOLDING AND DRIVING TJ'IECHANSl/lf.
- Application led October 30, 1922. SerialNo. 597,713.
improvement in rlool' Holding and Driving Mechanism, land declare the Yfollowing to be a tull,` cle-ar, and exact description or the same, such as will enable others skilled: in the art to which it pertains to make. and use .the same, reference being had t0,v the accompanying drawings, which form' apart ot this specilication. 4
My invention relatesy to improved toolholding and driving mechanism of simple, sturdy construction. An. object is to provide in'iproved tool-holding and driving mechanism of simple, sturdy, efficient design which is so constructed that in tapping, drilling, bolting, studsetting or other'operations the tool-holding portion. of the mechanismI may be released from. the driving power when the imposition of resistance t0 the rotation oft the tool approaches the danger point. i
It is well known that in such operations tools are frequently broken due tol a sudden increase in, restraint ot'rotation.; reamers doA not lino upwith the aperture to be reamed andl breakageI is the. result, and in multiple working increase in,` downward pressure upon certain ot thetools due to the completion of theI operations by certain other tools in the. series Afrequently causes tools upon which the pressure is increased to break under the strain. y
lvy invention, con'iprises anA improved construction which permits: release olf the tool troni. the driving iorce upon. dangerous increase of resistance torotation and continued. overrunning by the driving member of the driven tool-holding member during,
the vstoppage thereot,v operable, however, to automatically re-engage saidmembers for rotation upon reversal of the relative rotation oit said members.
The above and other objects, together with particular eatm'esv ot, construction, will more fully1 appear, .trom the following description, appended. claims and accompanying drawings, in which my invention is yshown as embodied in connection with a toolfholding. chuck, though. it is apparent 4 that the release mechanism might .he incorporated'v betweenl driving and driven spin-A dles at any point desired. 'f
In the drawings, Figure lis al side elevation of' my improved chock, partly broken away.
Fig. 2v is a verticalfsection through the barrel portion of the chock taken on .line HMH; of Fig. 2.
n Fig. 3` is a cross-sectional view taken on the line III-III of Fig. 2.
Fig. 4 is a cross-sectional view taken on the line TLV-lV, of Fig. 2.
Fig. 5 is a perspective of one of the cam levers 42. f f
Fig. 6 is a perspective of one of the vertically movable camsit-(i.
Fig. is a broken away vertical sectional view through the barrel.
Fig. 8 is a sectional: Viewl taken onl the same line as Fig. 3 showing the tool-holding' member and driving member` coupledy together ttor driving. v V v l F ig. 9 is a` sectional view taken on the line 9?-9 of Figz. v
Fig. l0. is a` verticaly sectional view'taken on thev line l0-10 ofFig. 1l.
Fig. l1 is a. horizontal*sectional view through a modiliedformof my deviceftaken on the same line as Fig, B. l y
Fig, 12f1is'agperspectiveV ofa slidable cam.
My improved. tool` comprisesy a, drivingv niembe and a driven?tool-holding member adapted, to be releasably coupled withy said driving. memberv to. rotateA therewith but which coupling islet such a character as to permit said; driving member to. rotate independently, of the tool-holding member when v the rotationol" the tool is obstructed tosuch a. degree as to approach the danger point ot' breakage thereof. y
ln the drawings, let 2() indicate the driving member providedl with` a suitable shank andy having an enlarged .head 21 whichy providedwith. an exterior shoulder 22thatr serves .as a. support igor-a bally race 23, upon one ymember .ot which race. is threaded a barrel 2,4'. It will be seen, therefore, that the driving member has ai rotation'relativc to the barrel` and the barrel is so formed at the lower end, asV to receive atool-holding socket 25wvliiel1yis secured tothe barrel` by means of a` suitable pivot pin, 26- so as. to provide tor hunted floatingA movement ot the socket and carried tool relatlvc the barrel. rlfhe lower portion of the socket is adapted toV removably receive a tool, not shown in lthe drawing. So `as to yieldingly preserve the vertical alinement of the tool and socket relativeeach other, I yprovide `spiral springs -27 and 28,v which, however,v i are, yas will be seen, yieldable to permit pivvota'l movement ofthe toolsoclret'so that the tool may be ydriven though it is not alined 4axially with the driving member'. i
, The head 2l of the driving member is diav metrically recessed as at 29, which diametri-l cal recess is provided with an axial recess 30. l provide adriving head 3l having a diametrically arranged portion 32 which is disposed within the diametrical recess 29 in.
.the head 2l and the* portion is provided -with a stein 33 receivable within the recess 30 in the head 2l. Surrounding Athe stem A.is a spring 34 which exerts downward pressure Aon thedriving head 3l. As, shown in Fig.` 2, I have provided arplurality of springs 34 bearing downwardly on the driv ing head. It is obvious that such a number of these springs might be provided as was found most suitable for the purpose.
` Positioned in the bottom of the barrel is a hearing plate 35, which Iis shown as locked I to depend below the lower facevof the drivhead. These rollers are adapted to enl .zo
this vrecess 39 are two slidably disposed' 'blocks 40 held outwardly therein by means liaco ot the bearing plate gage in opposite endsof a diametrical recess 39`fo'rmed in theibeari'ng plate 35 to pro-v duce rotation of .the bearing plate as one piece with the driving vhea-d 3l. Mounted in of a spiral vspring 41,..the upper surfaces of which blocks lie flush withthe upper sur- Pivoted to l' each block is a cam lever 42 which. is secured to v'the bearing plate by means of a vertical v lever.
studv 43 which travels'in a slot 44 in the Each lever is beveled at the free end as .at 45 for a'purpose hereinafter described. The normal position of the blocks and levers Vis shown in Fig. 3, inwhich the blocks areheld outwardly 1n the recess so as to prevent engagement of the rollers therein as they travel `over the face of the plate 35.'
' The driving head 3l carries in addition to the rollers'37 a pair of vertically movable Acammembers 46 shown` in perspective in Fig. 6. These cams are disposed in verticalv openings extending through the driving "head which are shaped to receive thev cam and each cam is providedwith 'a flange' 47 which rests upon the upper surface of thel driving head. Each cam isheld downwardly by means of a spring 48, one end of which engages the lower end of the head 21 and the other end of the spring is received over a stud 49 formed on the upper end of the cam46. The cams are narrowed to anedge at one end as at 50 and-the opposite end of the cam is beveled as at 5l. In the forward movement of the driving member when disengaged from the plate 35, and the blocks are held outwardly by means of `the spring 41, these cams 46 travel up over the cam levers 42, the beveled end 5l of the cam riding up over the beveled end vof the lever and the cam yielding vertically upwardly against the resistance of vits spring 48.' when the rotation of the working tool is impeded and the` driving member is rotated independently of the tool, or as shown in Fig. 3,' in which the cams and rollers appear lin dottedoutline.` 'y 1 Upon reversal of the rotation of the driving'member the'edge 50 of the .cam engages the side of the lever 42 in such a manner that the two cams tend .to force the levers in 5 the direction shown in Fig.l 8 so that the blocks 40'are withdrawn against the resist- This is the movement which occurs ance of the spring 4l, opening thev opposite ends of the passageway 39 so that continued rotation of the driving` head brings the rollers V3"(v into position to fall within this recess engaging the bearing plate 35 for rotationwith the driving head. i The position of the cams and levers is then as indicated in Fig.'8 and the tool is in the operative position. p
, In Figs.r l0, 11 and 12, I have shownA a modified `form of construction in that in stead ofthe cams 46 engaging the two levers 42, these cams engage a single slidable block beveled as shown in Fig. l2, which block is provided with a baseplate 5l disposed lwithin a radial recess formed in the bearing.
platel 35v for reciprocal radial movement therein. It held outwardly by means of a spring 52 but the extent of outward movenient is limited by a stop 53 carried bythe plaie 35 which extends upwardly inra slot `54 formed in the.base plate. This block 50 hastwo angularly disposed faces `which intersect at a point 55 that is disposed between the ends of the levers 42. These levers are pivoted to the blocks 40 ask heretofore setl forth butv project loutwardly' in a different fashion so thatfeach lever is acted upon by the block .50 at the same time and inward Y* movement of the block` 50 spreads'the-outer ends of the levers apart andpbrings .the inner ends togetherwithdrawing the blocks 40 against the tension of the spring 4l to permit .the rollers to engage in the recess 39.
l/Vhen the driving head is locked to the bearing plate 35 it will be vseen that the tool may be rotated as desired but that when ythe tool strikes an obstruction, producing suffiiso Iii
cient resistance to its rotation, release otthe rollers 'trom the recess 39 will automatically occur. the springs 34 yielding to permit suoli l' release, and the driving head Will rotate independently, overrunning` the tool-holding` is reversed, at which time the' action of thev cams as above described will retract the blocks 40 so as `to 'permit tlie rollers to en- ,e'agre in the recess in the bearing` plate, Withdraivinn; the 'tool and permitting reversal ot rotation to again operate the tool in the vforward direction.
1What l claim is:
l. ln a device ot the class described, in conibination, a. driving member, a driven tool-holding; member, rollers carried'by one member held under spring* pressure to engage said other member to cause said members to rotate as one piece. and releasable to permit independent overrunningrotation ot said driven member by said driving mem-` beil upon imposition of resistance to rotation upon said driven member sullicient to overcome the spring pressure'` on said rollers, and means operable to prevent reen gagement of said rollers during said over'- running' rotation. i
ln a. device or" the class described, in coiifibination, a driving member, a driven tool-holding' member, rollers carried by one member held under springl pressure to engage said -other member to canse said members to rotate as one piece in' the torivard direction and releasablefto permit said 'driving member to rotate independently of `said driven member in such forward direction upon imposition, of resistance to rotation upon said driven member sufficient to overconie said spring pressure and e'liect release ot said rollers 'trom driving' engagement, and means automatically operable to `prevent reengagrement ot said rollers during' the independent Vforward rotation otsaid driving' ineinlier` said means tiirtlier operable upon reversal ot rotation ot said drivinev member to permit ifs-engagement ot said rollers to pick up `said driven member tor rotation.
.fain depressions, and means operable to preo. In a device of the class described,inv combination, a'driving member, -a 'driven' vent re.-'engagement ot said rollers in said depressions yduring the continuance oit rotation ot' said driving member. y
4. In a device of the class described,'inl combination, a driving` member, a driven tool-holding member, rollers carried by one.A
o'tl said members, a bearing, plate. toi" said rollers cariied by said-'other member provided ivith depressions Within which' said rollers may engage to couple said members together to 'rotate as one piece inthe forivai'd direction, springmeans holdino' said rollers uiid'er pressure. to engagein said dcpressions yieldable to permit disengagement of said rollers from said depressions to permit independent rotation ot' said driving member in such 'forward direction, and' means automatically operable to prevent re.- engagement of said rollers in said depressions during the continued forward rotation of said driving member operable to permit such rei-engagement upon reversal of rot-ation of said driving member.
5. In a device oit the vclass described, in combination, a driving member, a ldriven tool-holding member, rollers carried by one of ,said members, a 'bearing plate for `said rollers carried by ksaid other member provided With depressions Within 'which said rollers may engage to couple said members together to rotate as one piece inthe forivard direction, spring means holding said rollers under pressure to engage in said -depressions, spring-controlled vmeans operable to prevent re-engagement ot said rollers in il said depressions during the continued toi'- Wai'd rotation of said driving member.
6. ln a device of theclass described, in combination, a drivingr` member, a driven tool-holding member,,rollerscarried by one ot' said members, a bearing plate 'tor said rollers carried by said other member provided Witli depressions Within which said rollers `may engage to couple said members togetl'ier to rotate as one piece in the 'tor- Ward direction, spring means holdingl said rollers under pressure to engagel in said depressions, spring-controlled means operable to prevent i'e.engageinent ot said rollers in said depressions during' the continued torivard rotation ot said dri-ving membeivre-v leasable 'to permit such yre-'engagement upon vreversal of rotation ot said 'driving member.
7. In a device of the class described, in
ycombinati-on, a *driving member, a' driven
US597713A 1922-10-30 1922-10-30 Tool holding and driving mechanism Expired - Lifetime US1537628A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US597713A US1537628A (en) 1922-10-30 1922-10-30 Tool holding and driving mechanism

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US597713A US1537628A (en) 1922-10-30 1922-10-30 Tool holding and driving mechanism

Publications (1)

Publication Number Publication Date
US1537628A true US1537628A (en) 1925-05-12

Family

ID=24392638

Family Applications (1)

Application Number Title Priority Date Filing Date
US597713A Expired - Lifetime US1537628A (en) 1922-10-30 1922-10-30 Tool holding and driving mechanism

Country Status (1)

Country Link
US (1) US1537628A (en)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2463083A (en) * 1947-08-11 1949-03-01 Charles Drexler Overload releasing toolholder
US2626644A (en) * 1949-08-09 1953-01-27 F M Ball & Co Overload release for pitter drive mechanism
US2629417A (en) * 1947-10-13 1953-02-24 Fruit Machinery Company Fruit splitter and pitter
US2802557A (en) * 1955-03-16 1957-08-13 Cleveland Rock Drill Division Self releasable clutch
US3199644A (en) * 1963-09-24 1965-08-10 Ingersoll Rand Co Automatic releasing clutch mechanism responsive to torque loads for use in power tools
US3958397A (en) * 1973-04-04 1976-05-25 Massey-Ferguson (Australia) Limited Torque limiting devices

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2463083A (en) * 1947-08-11 1949-03-01 Charles Drexler Overload releasing toolholder
US2629417A (en) * 1947-10-13 1953-02-24 Fruit Machinery Company Fruit splitter and pitter
US2626644A (en) * 1949-08-09 1953-01-27 F M Ball & Co Overload release for pitter drive mechanism
US2802557A (en) * 1955-03-16 1957-08-13 Cleveland Rock Drill Division Self releasable clutch
US3199644A (en) * 1963-09-24 1965-08-10 Ingersoll Rand Co Automatic releasing clutch mechanism responsive to torque loads for use in power tools
US3958397A (en) * 1973-04-04 1976-05-25 Massey-Ferguson (Australia) Limited Torque limiting devices

Similar Documents

Publication Publication Date Title
US1537628A (en) Tool holding and driving mechanism
US2522217A (en) Composite bit device for screw drivers and the like
US2526998A (en) Self-centering detachable coupling for machine tools
US2045572A (en) Overload safety device
US2491605A (en) Chuck
US1886177A (en) Boring tool and holder
US1527757A (en) Automatic chock
US2105788A (en) Stud setter
US4204303A (en) Locking mechanism for machine tool holder/adapter
US3152811A (en) Quick-action chuck for drilling and milling tools
US1363398A (en) Engine-valve
US1422058A (en) Tool holder
US2906541A (en) Tool adapter
GB825133A (en) Improvements in or relating to torque-limiting tool holders
US1593732A (en) Coupling mechanism
US2676809A (en) Toolholder bushing
US1174997A (en) Chuck.
US1905879A (en) Valve seat ring driver
US1817591A (en) Tool retainer
US1837403A (en) Dental handpiece chuck
US2680257A (en) Hand tapping machine
US2579382A (en) Retainer
GB592462A (en) Automatic centre punches, chisels, hammers and like impact tools
GB488242A (en) Improvements in or relating to devices for counter-sinking, boring, drilling and similar operations, provided with a depth stop
US3697186A (en) Hard start tool holder