US3034547A - Power-operated driver for threaded fasteners - Google Patents

Description

May 15, 1962 H. F. cox, JR., ETAL 3,034,547

POWER-OPERATED DRVER FOR THREADED FSTENERS Filed Aug. 24, 1959 6 Sheets-Sheet l Hor/my a Ax/ALLY FIGH INVENTORS DURLN N VAN ALSTYNE HERBERT F COX JR BY W ATTORNEY H. F. cox, JR., ETAL 3,034,547

May 15, 1962 POWER-OPERATED DRIVER FOR THREADED FASTENERS 6 SheecS-Sheei'I 2 Filed Aug. 24, 1959 INVEN N N VAN AIST HERBERT F COX.JR.

DURLI May 15, 1962 H. F. cox, JR., ETAL 3,034,547

PowER-oPERATED DRIVER RoR THREADED FASTENERS 6 Sheets-Sheet 3 Filed Aug. 24, 1959 INVENTORS DURLlN N-VAN ALSTYNE. HERBERT F-COX.JR.

ATTORN EY May 15, 1952 H. F. c'ox, JR., ETAL 3,034,547

POWER-OPERATED DRIVER FOR THREADED FASTENERS Filed Aug. 24, 1959 6 Sheets-Sheet 4 v INVENTORS DURLlN N.VAN ALSTYNE. HERBERT F. COX-JR.

ATTORNEY May 15, 1962 H. F. cox, JRA, ETAL 3,034,547

POWER-OPERATED DRIVER FOR THREADED FASTENERS Filed Aug. 24, 1959 6 Shee'c's--Sl'leecI 5 INVENTOR5 DURLIN N .VAN ALSTYNE. HERBERT F COX. J R,

ATTORNEY May 15, 1962 H. F. cox, JR., ETAL. 3,034,547

POWER-OPERATED DRIVER FOR THREADED FASTENERS 6 Sheets-Sheet 6 Filed Aug. 24, 1959 /lso ATTORNEY United States arent Patented May 15, 1962 3,034,547 POWER-OlERATllD DRIVER FOR 'ill-{READED FASTER-*ERS Herbert F. Cox, Jr., 406 Sedgwick Drive, Syracuse, NX.,

and Durlin N. Van Alstyne, Syracuse, N.Y.; said Van Alstyne assignor to said Cox Filed Aug. 24, 1959, Ser. No. 835,724 18 Claims. (Cl. 144.--32) This invention relates -to a driver for threaded fasteners and more particularly to a stud driver having center feed whereby a sequence of studs may be driven in rapid succession without the necessity of auxiliary feedmg equipment.

In stud drivers heretofore employed, it has been usual to provide separate apparatus to feed a single stud, one at a time to the stud driving chuck because of the fact that each individual stud must be gripped for the driving operation by a portion of its threads. The location of such feed apparatus is such as to interfere often with work requiring many closely spaced studs, and tends to limit the speed of operation. In an application tiled August 4, 1959, Serial No. 831,585, by Herbert F. Cox, Jr. and Durlin N. Van Alstyne, there is shown a center feed stud driver wherein a sequence of studs is fed to the driver through the hollow drive shaft. As set forth in that application, during the driving of a stud, the stud is held by threaded jaws complementally engaging a portion of the thread of the stud and the stud is prevented from rotating by being backed up by the next successive stud which is rigidly held against axial movement by jaws having complemental threaded faces, it being understood that mere axial thrust upon the second stud does not produce rotation of the second stud necessary for axial movement. The second stud therefore acts as a solid abutment to the stud being driven, because the stud being driven has no tendency to rotate the second stud except by the abutting contact, which contact is insuiiicient to impart rotation to the second stud against the friction of the jaws holding it.

In some instances, the studs being driven are formed by processes which create rough and untrue ends. For example, in the threading process the end thread may form an irregularity on the end of the stud, or the shearing process which originally cut the stud blanks to their proper length may produce a burr or irregularity on the stud end. Such irregularities could in eect create a jaw clutch effect between the driven stud and the backing up stud whereby torque, during driving, is transmitted from the driven stud to the backing up stud. Should this occur, the driven stud would transmit torque to the holding stud, and the resistance to turning of the driven stud, during the attempt at thread cutting would be transmitted to the second stud, and both studs would thread up ino the chuck together, destroying the rigid abutment normally afforded the stud being driven.

The present invention is directed to a construction wherein studs having such irregularities may be driven positively and Without danger of the effect described. The apparatus is similar in some respects and as to certain features to that disclosed in the application aforesaid, but the improvement is directed to an arrangement wherein the stud being driven and the successive stud are separated during the driving operation, there being provided means for entering the feed bore during the driving operation and establishing a blocking of the bore during the driving of the end stud independent of the following stud.

The various features of the invention will appear more fuhy hereinafter from the following detailed description when taken in conjunction with the accompanying drawings. It is expressly understood that the drawings are employed for purposes of illustration only and are not designed as a definition of the limits of the invention, reference being had for this purpose to the appended claims.

In the drawings wherein like reference characters indicate like parts:

FlGURE l is a side elevation of `the center feed stud driver;

FiGURE 2 is an end view of the stud driver, viewed from the bottom as from the line 2-2 of FIGURE 1;

FIGURE 3 is a longitudinal sectional view taken substantially on the line 3 3 of FGURE 2. The apparatus is shown in an intermediate return stroke position following the driving of a stud;

FlGURE 4 is a quarter sectional view taken on the line 4 4 of FlGURE 2 and shows the apparatus in an intermediate return stroke position following that of FIG- URE 3;

FIGURE 5 is a quarter section taken on the line 4 4 of FIGURE 2 showing the apparatus in its fully retracted position preparatory to commencing a cycle of operation;

FIGURE 6 is a quarter section taken on the line 4--4 of FIGURE 2 illustrating the apparatus at the bottom of its stroke immediately following the driving of a stud;

FlGURE 7 is a transverse section taken substantially on the line 7 7 of FIGURE 4;

FlGURE 8 is a transverse section taken substantially on the line 3 3 of FGURE 4;

FGURE 9 is a sectional view of a modified form of jaw of the type shown in FIGURE 3;

FIGURE 10 is a sectional view of a further modified form of a jaw; and

FIGURE il is a sectional view including a still further modilied jaw of the type shown in FIGURE 3.

Referring to FIGURES l and 3, there is shown a stationary driving head 20 which may be fixed to the arbor of apparatus corresponding to a drill press or the like, and such head is held rigid and stationary. The head comprises a depending housing or sleeve 22 within which is contained the stud driving assembly. Entering the head from above through an aperture 24 is a rotary drive shaft 25 having a hollow axial stud feed bore 28 which is vertically movable by any suitable power to provide the sequence of operation. Upon the lower end of the drive shaft 26 is a drive spindle 36 which is keyed to the drive shaft as at 32 (see ElGURE 6). Surrounding the spindle is a hollow sleeve 34 which is slidably disposed within the head sleeve 22. The sleeve 34 is provided with a longitudinal slot 36 which cooperates with a key 37 aixed to the spindle as by screws 35 whereby the sleeve 34 and the spindle 36 rotate together. The sleeve is axially movable with, and slidable with respect to the spindle at, or between, two end positions, the sleeve 34 being provided with spaced detent recesses 3S and 4b which cooperate with a detent ball 42. The recesses may be annular in extent to facilitate manufacture. The detent ball 42 is spring pressed and disposed in a radial aperture 44 in the spindle Si?. The ball 42 is urged outwardly against the internal wall of the sleeve 34 and into either one of the detent recesses 3S and 46 by the spring 45.

Th spindle 3d has a feed bore 4S coaxial with the bore 2S. The spindle 3d is provided on its exterior with four slots 50 and 52, and S4 and 56, within which are disposed primary and second fingers S8 and 6l), and 61 and 62. The primary fingers 5S and @il are pivoted on heavy transverse pins 64 and 66, and the secondary fingers 61 and 62 are pivoted on heavy transverse pins 68 and 7%, threaded into the spindle.

The primary hngers are alre and have arcuate jaws 72 having arcuate female thread faces 74 and 75 to coniplementally embrace a portion of the threaded exterior of a stud such as 76. The jaws have exterior arcuate cam follower faces 7S adapted to engage within the internal cylindrical wall Sil of the lower end of the sleeve 34. The radial spacing between the thread faces 74 and 75, and the arcuate faces 7d, is such `as to provide a solid grip of a portion of the threads of a stud such as 76, when the jaws are disposed within the cylindrical wall Sil of the sleeve 34, for example as shown in FGURESVZL and 5, wherein for illustrative purposes, the pnrnary linger Sh `and its thread face 74 are shown, and a fragmentary portion of the other primary linger jaw with its thread face 75 is also shown in section, for illustrative purposes only, 'to sho-w the grip upon the stud. The primary lingers are normally urged to a non-gripping position by leaf springs 79.

The secondary fingers 6l and 62 are provided with similar inwardly extending abutment ends S2 and at their lower ends, and cam followers 86 and SS `at their upper ends. The cam followers rotate with the spindle assembly and ride on the stationary internal cylindrical wall @il of the dependent head sleeve 22. rllhe internal wall is provided with an enlarged diameter cylindrical portion 92 at its lower end which connects with the internal cylindrical wall 9d through a conical wall' portion or conical cam 94. The lower ends 82 and S4 of the secondary lingers are adapted to swing into the position indicated in FIGURE 6, the linger 84 being shown in dotted outline, in view of the quarter section, in order to illustrate the position taken by its end 84. lt will be seen that when the secondary lingers are swung to the position indicated in FIGURE 6, or the secondary linger 61 has its lower end S2 in the position shown in FIGURE. 3, the upper faces 96 and 93 of the abutment ends either together, or singly, serve as a stop to prevent the feed of the second in line stud 76A, which in turn supports the Successive studs there-behind such as the next stud 76B. The lower ends of the secondary fingers are urged inwardly by leaf springs 199 and 192.

The secondary linger 62 dilfers from linger 61 in that the upper end thereof is longer and is bifurcated to provide a yielding dog 104 having a V edge 1196 adapted to engage between adjacent threads of a threaded stud such as 76B. The arm 104 is sufficiently slender Vand resilient so that should the V edge 166 engage the crest of a stud thread, the arm 104 will resiliently yield until the stud 76B drops one-half a thread pitch whereby the V edge will seat be-Y. tween the threads. lt will appear that the upper end of the secondary finger 61 will extend through the slot 36 to engage the inside wall of the head sleeve 22. it will also appear that the sleeve 34 is slotted lengthwise on the opposite side, as at 168, to permit the follower end SS of the secondary finger 62 to ride upon the internal wall of the head sleeve 22.

The secondary fingers 6l and 62y at their lower ends are provided with abutment faces 167 and 169, FlGURE 11, which when closed together in the manner indicated in FIGURE 6 form `an abutment for the upper end of a with a recess 132 in its upper end and in which the lower end of a threaded stud may nest. Such stop member 130 may be interchangeable with members of varied lengths and recesses to accommodate studs of different lengths, as will appear hereinafter. The member is conveniently threaded into the arm 123 as at 134 whereby stop members of dierent lengths may be readily interchanged. The arm 126 may be adjustably held upon the bridge member l2@ by screws 136.

The lower end of the sleeve 34 is provided with a nose 137, threaded upon ythe lower end of the sleeve as at 13S. rl`he nose forms a cap, that in turn has a coaxial guide sleeve 139 through which the respective studs pass and are guided during operation.

The internal cylindrical wall 80 yof the sleeve 34 terminates at its opposite ends with annular outwardly llaring conical camming surfaces 146 and 142.

Reference to FlGURES 3 through 6 will be had for a description of the `operation of the device. In FIGURE 5 the sleeve 34 and the spindle 3l? are in their uppermost position and the detent ball 42' is located in the detent groove 3S. The J edge 106 of the secondary linger 62 is engaged in the threads of the stud 76A, and is holding such stud from dropping down the bore 28 as by gravity, and is likewise holding a succession of studs there-behind in the bore 28. The primary lingers 5S and 6d are in gripping relation to the stud 76 ywhich is to be driven, by reason of the engagement of the circular faces 78 within the wall Sli of the sleeve 34.

The continuously rotating drive shaft 26, as it commences its downward movement toward the position shown in FIGURE 6, causes the sleeve 34 to descend with the spindle, it being held by the detent ball 42 lying in the detent recess 38. The spindle assembly, comprising spindle Si? and sleeve 34, thus moves downwardly as a unit. As the nose 137 of the sleeve 34 contacts the cam surface 124 of the shoe 110, the shoe is swung clear of the sleeve 34 to the position in which it `appears in FIG- URE 6. As the spindle assembly descends further, the lower end of the guide sleeve 139 of the nose 137 contacts the upper surface 16o of the workpiece 162. Thereafter relative axial movement takes place between the sleeve 34 Y and the spindle Sil, the spindle 30 continuing its movement stud such as 76 during the course of the driving of Vsuch stud.

Located upon the outside of the head sleeve 22 is a pivoted shoe 110 comprising spaced arms 112 and 114, FlG-V URE 8, which extend inwardly at their upper ends and are pivoted on pivot pins 116 and 118. The arms at their lower end are connected by a bridge member 129. Centrally of the bridge member there is provided an inwardly projecting tongue 122 having a cam surface 124, the function of which will appear hereinafter.

The bridge member 12@ is provided with an abutment or stop 125 which engages the external wall of the head sleeve 22, to limit the clockwise swinging movement of the pivoted shoe 11o. Adjustably secured to the bridge member is a depending `arm 126 that Vextends inwardly at its lower end to the aXis of the apparatus as at 128. Gn the end of such arm, there is provided a stop member 136 in the form of a boss, which stop member is provided downward while the sleeve 34 is prevented from further downward movement, such relative movement being permitted by the ball `42 moving `out of the detent recess 3S.

Further downward movement of the spindle 3l? projects the stud '76 into the aperture 164 of the workpiece, and rotatingly threads the stud 76 into the `aperture 164, thereby cutting or forming the lthreads in the aperture 164 as rotation and downward movement continue. During this portion of the operation, the arcuate faces 78 ride downwardly along the cylindrical wall S0 of the sleeve 34 and the thread faces 74 `and '7"5 are rigidly held in engagement with the threads of the stud. During this operation, the upper end of the stud 76 is in abutting relation with the under faces 107 and 169 of the secondary lingers 61 and s2;

It will appear that as the assembly including the spindle 3l) and 34 move downwardly, the cam follower end 86 of the secondary linger 61 rides along the internal cylindrical wall 91B of the head sleeve 22 until it reaches the annular conical cam portion 94 of the wall of the sleeve 22 which leads into the enlarged diameter cylindrical wall 92 of the sleeve 34. At this point, the spring urges the upper end of the secondary linger 61 outwardly and the lower end 32 inwardly :to the position shown for example in FlGURE 6, and such action takes place prior to the entrance of the stud into the workpiece aperture 164. Further downward movement of the spindle assembly, that is spindle 30 and sleeve 34, causes the cam follower end SS of the secondary nger 62 to ride into the annular conical cam 94 and into the enlarged cylindrical bore 92, whereupon spring 1il2 urges the upper end of linger 6'2 outwardly and the lower end 84 inwardly to the position indicated in dotted outline in FIGURE 6.

in order to permit the lower ends of the secondary ngers 61 and 62 to swing into position, the stud 76 is initially held so that its upper end is sufliciently low so as not to interfere with the arcuate swinging movement of 6l and 62, thus leaving a slight clearance space between the upper end of the stud and the faces lli and lil? of :the secondary fingers 6i and 62. The lingers 6l and 62 are in a position to abut the upper end of the stud and prevent axial movement of the stud relative to the spindle. When the stud enters the recess idd of the workpiece, its rotation is momentarially retarded and thereby caused to thread upwardly within the primary fingers 5S and 60 until the upper end of the stud strikes the abutment faces 107 and il9 of the lingers 6i and 62. hereupon further axial movement relative to the spindle is prevented and driving torque is transmitted to the stud 76 through the primary lingers 53 and 69* to cause the stud to rotate with the assembly, and form its thread and take its place within the recess 164i, the ultimate position of the stud 76 being that shown in FIGURE 6.

As the spindle 3b moves downwardly relative to the sleeve 34, the sleeve 34 abutting the workpiece 16d, the arcuate faces 78 of the iingers 58 and 6l? move downwardly along the cylindrical internal wall S9, until the detent ball 42 reaches the edge of the detent groove 4u, whereupon the sleeve snaps upwardly to seat the ball 42 in the groove 4i?, at which time the arcuate surfaces 7S reach the conical camming surface 14d whereupon the lower ends of the primary lingers 51 and 6d are allowed to move outward to immediately release their grip upon the stud 76, to 'take the position indicated in FiGURE 6.

At this point, the ball 42 has seated in the lower detent groove il in the sleeve 34. Upward movement of the rotating shaft 26 brings the spindle and sleeve 34 'upwardly within the non-rotating head sleeve 22, and the studs 76A and 76B and those following are lifted initially during the return movement. When the spindle and sleeve assembly have moved upwardly a sudcient distance, the shoe 11d swings into the position in which it is shown in FGURE 4, wherein the stop member 13b is in axial alignment with the feed bore of the apparatus. As the cam 124 permits the shoe to swing clockwise to the stop position of FiGURE 4, the cam follower 86 of the secondary nger 61 rides out of the cylindrical face 92, along the conical face 9d, and upon the cylindrical wall 98, thereby moving the lower end S2 of secondary linger 6l radially outward from beneath the stud 76A. Previously the cam follower surface SS of the finger 62 had ridden upon the cylindrical face 9d thereby projecting the V edge 195 into the threads or" the stud 76B to hold the stud 76B and those vfollowing it against downward movement within the bore 2?. Such movement radially retracted the nger end 84 from the path of the stud 76A. The radial outward movement of the lower end S2 of the secondary nger 61 clears the stud 76A, allowing it to drop until its end -nests in the end 132 of the stop i3() Ywhere it is held in proper position for subsequent gripping by the primary fingers 58 and 6b.

Further upward movement of the spindle and sleeve 34 brings the upper end 33 of the sleeve 34 into engagement with the sur-face 371 of the head 2d thereby arresting further upward movement of the sleeve 34. The spindle continues its upward movement causing the ball 42 to move out of the detent groove 4d, and upon further relative axial movement between the spindle and sleeve 34, the arcuate faces 78 of the primary fingers are caused to ride within the cylindrical face 89 of the sleeve 34 thereby drawing the primary lingers 5S and 6d together in gripping relation around the stud which is now 76A. Further upward movement of the spindle continues until the upper end 31 thereof engages the inside face 371 of the head 2li and all the parts are then in a position as d shown in FIGURE 5. The stud 76A now becomes the next stud in line for driving.

In FlGURES 9, l0, and ll, modified forms of secondary fingers 62 are shown. ln FIGURE 9 the finger 262 is provided with a spring leaf 264, the end of which is provided with a l edge 266 for engagement with the stud threads. in FIGURE l0 the finger 362 is provided with a spring arm 253 that is inwardly bent at 270 to provide a V edge for `engagement with the threads. In E GURE ll the nger 462 does not carry the V edge as in the other forms but the spring leaf employed .o urge the upper end of the linger outwardly is extended as at 2?4 to provide a V edge as at 27 6 for engaging the threads of the stud 76. it will be apparent that when the secondary linger 462 is rocked counterclockwise and moved `from the cylindrical surface 92 to the cylindrical surface its spring 274 will be urged yieldingly inward so as to engage the threads of the stud 76.

Although a single embodiment of the invention with several alternate details in respect to secondary lingers, has been illustrated and described, it is to be understood that the invention is not limited thereto. As various changes in the construction and arranvement may Ibe made without departing from the spirit of the invention, as will be apparent to those skilled in the art, reference will be had to the appended claims for a definition of the limits of the invention.

1`What is claimed is:

1. A center `feed driver for threaded fastener members comprising a drive spindle having a center bore for receiving a series of threaded members in sequence, means carried by the spindle for complementally gripping the threads of a threaded member having an end portion projecting beyond the end of the drive spindle bore, and means carried by the spindle for securing another threaded member of said series immediately following said first member within the bore against axial movement and in spaced relation to said iirst threaded member, and abutment means carried by the spindle adapted to be interposed in said bore lbetween the members, and `adapted to engage the other end of said first threaded member.

2. A center feed driver for threaded fastener members comprising a drive spindle having a center bore for receiving a series oi aligned threaded members in sequence, means carried by the spindle for complementally gripping the threads of a member With its end portion projecting beyond the end of the drive spindle bore, and means carried by the spindle for securing a second threaded member of said series within the bore against axial movement, in spaced axial relation to said tirs-t member and sleeve means disposed about said spindle and having axial movement relative to said spindle :for actuating said gripping means, and abutment means carried -by the spindle, and laterally movable into the bore between said members.

3. A center feed driver for threaded fastener members comprising a drive spindle having a center bore for receiving a series of aligned threaded members in sequence, means carried by the spindle for complementally gripping the threads of a member with its end portion projecting beyond the end of the drive spindle bore, and means complementally the spindle for secuning a second threaded member of said series within the bore against axial movement, in spaced axial relation to said iirst member, sleeve means disposed about said spindle and having axial movement relative to said spindle for actuating` said gripping and securing means, a sleeve housing surrounding said sleeve means and spindle, abutment means carried by the spindle and laterally movable into and out of the bore between said members, and means responsive to relative movement between said spindle and housing for actuating said abutment means.

4. A center feed driver for threaded fastener members comprising a drive spindle having a center bore for receiving a series of threaded members in sequence, laterally movable gripper means carried by the spindle for complementally gripping the threads of a threaded member havingY an end portion projecting beyond the end of the drive spindle bore, and means laterally movable into and out of the bore and carried by the spindle for intermittently blocking the bore of said spindle behind said projecting threaded member, and ahead of the second threaded member of said sequence, and means for holding said second member in axial spaced relation from said movable means during movement into said bore.

5. A center feed driver for threaded fastener members comprising a drive spindle having a center bore for receiving a series of threaded members in sequence, laterally movable gripper means carried by the spindle for complementally gripping the threads of a threaded member yhaving an end portion projecting beyond the end of the drive spindle bore, means carried by the spindle for intermittently blocking the bore of said spindle behind said projecting threaded member, and ahead of the succeeding threaded member, and sleeve means axially movable relative to said spindle for actuating said blocking means.

6. A center feed stud driver comprising a non-rotatable hollow head having an open ended sleeve, a drive spindle slidably and rotatably mounted within said head, having a center bore extending the length thereof for receiving a series of threaded studs in sequence, a sleeve slidably disposed on said spindle, and keyed for rotation therewith, and disposed between said spindle and open ended sleeve, radially and axially extending slots in said spindle, a primary nger pivoted in one of said slots, adapted to complementally grip the threads of a stud in said bore, and means responsive to relative movement between said intermediate sleeve and said spindle for controlling the operation of said primary nger and the grip and release of said stud, a secondary finger pivoted in another of said slots adapted to enter and block the bore behind said first named stud and to grip a stud located behind said first named stud, in spaced axial relation to said first named stud, and means responsive to relative movement between said spindle and said head sleeve for controlling the grip and release of said secondary finger upon said second stud.

7. A center feed stud driver comprising a non-rotatable hollow head having an open ended sleeve, a drive spindle slidably and rotatably mounted within said head, having a center bore extending the length thereof for receiving a series of threaded studs in sequence, a sleeve slidably disposed on said spindle, and keyed for rotation therewith, and disposed between said spindle and open ended-sleeve, radially and axially extending slots in said spindle, a primary finger pivoted in one of said slots, adapted to grip a stud in said bore, and means responsive to relative movement between said intermediate sleeve and `said spindle for controlling the operation of Lsaid primary finger and the grip and release of said stud, a secondary finger pivoted in another of said slots adapted to grip a stud located behind said first named stud, in spaced axial relation to said rirst named stud, and means responsive to relative movement between said spindle and said head sleeve for controlling the grip and release of said secondary nger, Vupon said second stud, said secondary nger having abutment means adapted to enter the bore behind said first named stud, upon the release of said second stud.

' 8. A center feed stud driver comprising a non-rotatable hollow head having an open ended sleeve, a drive spindle slidably and rotatably mounted Within said head, having a center bore extending the length thereof for receiving a series of threaded studs in sequence, a sleeve slidably disposed on said spindle, and keyed for rotation therewith, and disposed between Said spindle and open ended sleeve, opposed pairs of radially and axially extending slots in said spindle, primary lingers pivoted in one pair of said slots, having jaw portions at their lower ends adapted to grip the threads of a stud beyond s Y s S g the Yend of said bore, and means responsive to relative movement between said intermediate sleeve and said spindle for controlling said fingers and their grip and release of said stud, secondary ngers pivoted in the other pair of said slots having abutments adapted to enter said bore behind the jaw portions of said primary fingers, and means responsive to relative movement between said spindle and said head sleeve for controlling said secondary ngers to move said abutments into and out of said bore.

9. A center feed stud driver comprising a non-rotatable hollow head having an open ended sleeve, a drive `spindle slidably and rotatably mounted within said head,

v having a center bore extending the length thereof for receiving a series of threaded studs in sequence, a sleeve slidably disposed on said spindle, and keyed for rotation therewith, and disposed between said spindle and open ended sleeve, opposed pairs of radially and axially extending slots in said spindle, primary fingers pivoted in one pair of said slots, having jaw portions at their lower ends adapted to grip the threads of a stud beyond the end of said bore, and means responsive to relative movement between said intermediate sleeve and said spindle for controlling sa-id ngers and their gr'ip and release of said stud, secondary fingers pivoted in the other pair of said slots having abutments adapted to enter said bore behind the jaw portions of said primary fingers, means responsive to relative movement between said spindle and said head sleeve for said secondary fingers to move said abutments into and out of said bore, and means on one of said secondary fingers adapted to enter said bore to engage the threads of an intermediate stud in said bore upon the movement of the labutment end of said one secondary iinger out of said ore.

l0. A center feed threaded stud driver comprising a housing, a spindle assembly comprising a spindle and sul'- rounding sleeve rotatable and reciprocatable within said housing, said sleeve being axially slidable on said spindle, and rotatable therewith, said spindle having an axial feed bore to receive a succession of studs, means on said housing for axially positioning a stud located beyond the end of said spindle, means on said spindle and actuated by relative movement between said spindle and sleeve for gripping a stud by its threads positioned by said positioning means, means on said spindle, and actuated by relativeV axial movement between said spindle and housing for blocking and unblocking the bore of said spindle behind said positioned stud, and supporting a second stud within said bore upon blocking thereof, and means responsive to relative movement between said spindle and housing for retaining a third stud against axial movement in said bore upon the unblocking of said bore by said blocking means.

11. A center feed driver for threaded fastener members comprising a non-rotatable hollow head having an open ended sleeve, a drive spindle slidably and rotatably mounted within said head having a center bore extending the length thereof for receiving a series of threaded members in sequence, a sleeve slidably disposed on said spindle and keyed for rotation therewith, and disposed between said spindle and open ended sleeve, detent means for yieldingly holding said sleeve in one or the other of two end positions, two sets of opposed radially and axially extending slots in said spindle, a pair of primary iingers pivoted in one set of said slots, adapted to grip the threads of a member in said bore, and means responsive to relative movement between said intermediate sleeve and said spindle between said detent held positions for controlling the grip and release of said member, a secondary linger pivoted in another of said slots having an abutment entering the bore behind said member and adapted to block the bore and support a second member located above said first named member and means responsive to sleeve for controlling the movement of said secondary finger abutment into and out of said bore.

12. A center feed driver for threaded fastener members comprising a non-rotatable hollow head having an open ended sleeve, a drive spindle slidably and rotatably mounted within said head having a center bore extending the length thereof for receiving a series of threaded members in sequence, a sleeve slidably disposed on said spindle and keyed for rotation therewith, and rl'sposed between said spindle and open ended sleeve, detent means for yieldingly holding said sleeve in one or the other of two end positions, two sets of opposed radially and axially extending slots in said spindle, a pair of primary fingers pivoted in one set of said slots, adapted to grip the threads of a member in said bore, and means responsive to relative movement between said intermediate sleeve and said spindle between said detent held positions for controlling the grip and release of said member, a secondary linger pivoted in another of said slots having an abutment entering the bore behind said member and adapted to block the bore and support a second member located above said rst named member and means responsive to relative movement between said spindle, said head sleeve for controlling the movement of said secondary linger abutment into and out of said bore, and means for blocking and unblocking said bore beyond the end responsive to relative movement between said head and intermediate sleeve.

13. A center feed driver for threaded fastener members comprising a non-rotatable hollow head having an open ended sleeve, a drive spindle slidably and rotatably mounted within said head having a center Vbore extending the length thereof for receiving a series of threaded members in sequence, a sleeve slidably disposed on said spindle and keyed for rotation therewith, and disposed between said spindle and open ended sleeve, detent means for yieldingly holding said sleeve in one or the other of two end positions, two sets of radially and axially extending slots in said spindle, a pair of primary fingers pivoted in one set of said slots, adapted to grip the threads of a member in said bore, and means responsive to relative movement between said intermediate sleeve and said spindle between said detent held positions for controlling the grip and release of said member, a secondary finger pivoted in another of said slots having an abutment entering the bore behind said member and adapted to block the bore and support a second member located above said rst named member, and means responsive to relative movement between said spindle and said head sleeve for controlling the movement of said secondary finger abutment into and out of said bore, a second secondary finger in the remaining slot having means for engaging a third member in said `bore and holding the same against axial movement therein.

14. A center feed driver for threaded fastener members comprising a non-rotatable hollow head having an open ended sleeve, a drive spindle slidably and rotatably mounted within said head having a center bore extending the length thereof for receiving a series of threaded members in sequence, a sleeve slidably disposed on said spindle and keyed for rotation therewith, and disposed between said spindle Iand open ended sleeve, detent means for yieldingly holding said sleeve in one or the other or" two end positions, two sets of radially and axially extending slots in said spindle, a pair o-f primary lingers pivoted in one set of said slots, adapted to grip the threads of a member in said bore, and means responsive to relative movement between said intermediate sleeve and said spindle between said detent held positions for controlling the grip and release of said member, a secondary finger pivoted in another of said slots having an abutment entering the bore behind said member and adapted to block the bore and support a second member located above said Erst named member, means responsive to relative movement between said spindle and said head sleeve for controlling the movement of said secondary nger abutment into and out of said bore, a second secondary finger in the remaining slot having means for engaging a third member in said bore and holding the same against axial movement therein, and means responsive to relative axial movement between said spindle and said head sleeve for releasing said third member following an unblocking and subsequent blocking of the bore by said rst named secondary finger, and means for blocking and unblocking said bore beyond the end responsive to relative movement between said head and intermediate sleeve.

15. A center feed driver for threaded fastening members comprising a relatively stationary head having a depending hollow sleeve, a spindle and sleeve assembly disposed within the sleeve of said head and aiiixed upon a rotatable and axially movable drive shaft extending downwardly through said head, said sleeve being splined to said spindle and axially movable relative to said spindle, detent means for yieldingly holding said sleeve on said spindle in two axially spaced end positions, a center feed bore for threaded members extending axially through said shaft and said spindle, two pairs of opposed radial lengthwise extending slots in said spindle, lying in planes transverse to one another, and slots in said spindle sleeve radially aligned with one of said pairs of slots in said spindle, the slots in said one of said pairs having apertures extending to the spindle bore adjacent their lower ends, two opposed iingers pivoted centrally thereof on transverse axes within said one of said pair of slots, said ngers having at their lower ends radially inwardly projecting abutments adapted to project through said apertures to the axis of said bore, and cam followers at their upper ends adapted to project outwardly through said sleeve slots, said head sleeve having a cylindrical cavity having upper and lower annular inclined cam faces adapted to engage said cam followers on relative axial movement between said spindle and head, means for yieldingly urging said abutments radially inward, a pair of stud gripping fingers pivotally mounted centrally thereof within said other pair of slots on transverse axes, said gripping lingers having complemental thread engaging jaw faces at their lower ends disposed immediately beyond the end of said spindle, and radially outwardly extending cam follower portions at their lower ends, said spindle sleeve having an inwardly projecting cylindrical cam face having an annular outwardly inclined face at its lower end adapted to coact with said gripping finger cam follower portions upon relative axial movement between said spindle and spindle sleeve, said last named cylindrical face acting to hold and lock said gripping linger jaw faces upon a threaded member through the lower cam followers of said gripping fingers, means for blocking and unblocking the bore below the end thereof pivotally mounted on the head sleeve on a transverse axis to one side of the bore axis, said blocking means having a stop coaxial with the bore axis when said spindle assembly is retracted upwardly within said head, and having cam means coacting with said spindle assembly for swinging said blocking means laterally and clear of said spindle assembly when projected to drive a threaded member.

16. A center feed driver for threaded fastener members comprising a non-rotatable hollow head having an open ended sleeve, a drive spindle slidably and rotatably mounted within said head having a center bore extending the length thereof for receiving a series of threaded members in sequence, a sleeve slidably disposed on said spindle and keyed for rotation therewith, and disposed between said spindle and open ended sleeve, detent means for yieldingly holding said sleeve in one or the other of two end positions, said spindle having two sets of opposed radially and axially extending slots, said sleeve having slots aligned with one of said sets of spindle slots, a pair of primary ngers pivoted in the other set of said slots, having jaws adapted to grip the threads of a member projecting from the end of said bore, and means responsive to relative movement between said intermediate sleeve and said spindle between said detent held positions for controlling the grip and release of said primary ngers upon ,said member, secondary lingers pivoted in each of the first named set of slots having blocking means adapted to enter the bore behind said tirst named member and prevent axial movement of said member, and means responsive to relative movement between said spindle and said head sleeve for sequentially moving the blocking means of said secondary lingers into and out of said bore, said blocking means being adapted to support a second member above the first member, and one of said secondary ngers having means to engage and hold a third member, upon movement of its blocking means from said bore in advance of the movement o the blocking means of the other secondary iinger from said bore.

17. In a center feed driver for threaded fastening members, a housing having a depending sleeve, a rotary spindle disposed therewithin, and axially movable relative to said sleeve, said sleeve having an internal conical cammingsurface axially interposed between adjoining internal cylindrical wallsthe wall above being of lesser diameter than the wall below, said spindle having an axial bore, opposed fingers pivotally mounted intermediate their ends on transverse axes in said spindle, said opposed fingers at their lower ends having symmetrical inwardly extending portions adapted to enter said bore and form supporting abutments for a column of threaded members in said bore and said lingers at their upper ends having outwardly facing cam followers adapted to ride on the internal wall of said sleeve for actuation by said conical cam surface on relative axial movement between said spindle and sleeve, one of the upper ends of said ngers being longer than the other, and having means for engaging the threads of and holding the second threaded member in said column when moved radially inward by said conical cam, and the supporting abutments of both of said ngers being adapted to be radially retracted from said bore upon actuation of the follower ends thereof inwardly by said conical cam, whereby the first of said members of the column is released while the second is held, and the second released by its holding linger only while the abutment of the other iinger is in supporting position within the bore.

s Y Y 12 Y 18. In Va center feed driver for threaded fastening members, a housing having a depending sleeve, a rotary spindle disposed therewithin, and axially movable relative to said sleeve, said sleeve having an internal conical camming surface axially interposed between adjoining internal cylindrical Walls, the wall above being of lesser diameter than the wall below, said spindle having an axial bore, opposed ngers pivotally mounted intermediate their ends on transverse axes in said spindle, said opposed lingers at their lower ends having symmetrical inwardly extending portions adapted to enter said bore and form supporting abutments for a column of threaded members in said bore and said ngers at their upper ends having outwardly facing cam followers adapted to ride on the internal wall of said sleeve -for actuation by said conical cam surface on relative axial movement between said spindle and sleeve, one of the upper ends of said fingers being longer than the other, and having means for engaging the threads of and holding the second threaded member in said column when moved radially inward by said conical cam, and the supporting abutments of both of said lingers being adapted to be radially retracted from said bore upon actuation of the follower ends thereof inwardly by said conical cam, whereby the first of said members of the column is released while the second is held, and the second released by its holding finger only while the abutment of the other finger is in supporting position within the bore, and means carried by the spindle for gripping a portion of the threads of the released member immediately below said abutments, for driving said stud with its upper end jammed against the underside of said abutments.Y

References Cited in the le of this patent UNITED STATES PATENTS 1,125,186 Schneider Jan. 19, 1915v 2,256,012 Blair Sept. 16, 1941 2,575,525 Mitchell Nov. 20, 1951 2,589,016 Michatek Mar. 11, 1952 2,719,445 Giebler Oct. 4, 1955 2,760,394 Wragge Aug. 28, 1956 2,876,668 Phillips Mar. 10, 1959

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