Impact tool

Nov. 20, 1951

J. C. LANG

IMPACT TOOL

2,575,455

Filed Nov. 5, 1946 8 Sheets-Sheet 1

<img file="US2575455A_D0001.tif" />

Fig. J.

Nov. 20, 1951

J. C. LANG

IMPACT TOOL

2,575,455

Filed Nov. 5, 1946

Sheets-Sheet 2

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Nov. 20, 1951

J. C. LANG

IMPACT TOOL

2,575,455

Filed Nov. 5, 1946 8 Sheets-Sheet 3

<img file="US2575455A_D0003.tif" />

-Fig. 3.

Nov. 20, 1951

J. C. LANG

IMPACT TOOL

2,575,455

Filed Nov. 5, 1946 8 Sheets-Sheet 4

<img file="US2575455A_D0004.tif" />

Nov. 20, 1951

2,575,455

J. C. LANG

IMPACT TOOL

Filed Nov. 5, 1946

<img file="US2575455A_D0005.tif" />

J---3Z

Sheets-Sheet δ

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Fly- 6.

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<img file="US2575455A_D0008.tif" />

INVENTOR.

<img file="US2575455A_D0009.tif" />

9.

Nov. 20, 1951

2,575,455

J. C. LANG

IMPACT TOOL

Filed Nov. 5, 1946 8 Sheets-Sheet 6

<img file="US2575455A_D0010.tif" />

Nov. 20, 1951

J. C. LANG

IMPACT TOOL

2,575,455

Filed Nov. 5, 1946

Sheets-Sheet 7

<img file="US2575455A_D0011.tif" />

INVENTOR.

<img file="US2575455A_D0012.tif" />

Nov. 20, 1951

J. C. LANG

IMPACT TOOL

2,575,455

Filed Nov. 5, 1946

Sheets-Sheet 8

<img file="US2575455A_D0013.tif" />

Patented Nov. 20, 1951

2,575,455

UNITED STATES PATENT OFFICE

2,575,455

IMPACT TOOL

Joseph C. Lang, Pittsburgh, Pa., assignor to Bocjl Corporation, Pittsburgh, Pa., a corporation of Delaware

Application November 5,1946, Serial No. 707,949

Claims.

This invention is for an impact tool and relates particularly to a tool in which rotary motion is transformed into a reciprocating motion, and wherein a driver is operated with sudden force.

The Invention relates particularly to a machine for driving tacks, and particularly tacks in strip form, disclosed in my copending application Serial No. 636,467, filed December 21, 1945. It will be specifically described in this connection, but the invention may be otherwise embodied and is not restricted to the particular driver herein disclosed.

In many industries, such for example as the furniture upholstery industry, large quantities of tacks are required to be driven. Persons trained in the art of driving tacks are frequently known as “tack spitters,” by reason of the fact that when working they place a hand full of tacks in their mouths. They remove them one at a time to drive them. At the end of a particular operation, if one of them should happen to have a quantity of tacks in his mouth, he spits them away, and in many industries it is probable that the number of tacks thus wasted equals or exceeds the number used. Stringent sanitary rules regulate plants of this kind to prevent the re-use of the tacks. Large quantities of tacks are frequently strewn over the floor.

A further difficulty is that such workmen require a high degree of training before they are sufficiently skillful to work rapidly and accurately, and since the furniture is usually completely finished so far as woodworking is concerned, before the upholstering is done, it not infrequently happens that furniture is ruined or expensive reflnishing operations are required by reason of such an operator hitting the wood finish in driving home the tack.

In my copending application Serial No. 636,467, filed December 21, 1945, 1 have disclosed a tacklike fastener which is designated a T-tack. It is formed from a narrow strip or ribbon of metal which is slit diagonally from one edge toward the center, and then longitudinally of the strip to form a succession of tack or fastener blanks. The margin of the ribbon of metal which is so slit constitutes the leg-forming element of the tack. In operation it is bent about an axis transverse to the longitudinal axis of the ribbon into a position perpendicular to the original plane of the metal to form a T-shaped blank with the head of the tack being to one side of the leg, and being comprised of that part of the strip of metal which is not slit. The strip so formed is cut at regular intervals with the leg-forming element about midway of the length of the head to form the individual fasteners. It is intended that the steps of bending down the leg, cutting off the blank, and driving it, be accomplished in the driving machine, and in my application Serial No. 634,537, (Cl. 1—51) filed December 12, 1945,1 have disclosed a feeder for advancing such a blank strip into a driver.

To drive a tack or fastener of this kind, it is necessary that the tack be hit a quick, sharp, hard 5 blow, and it is also necessary that insofar as possible, the leg of the fastener shall be guided against bending, particularly when the fastener is initially entering the wood or other substance into which it is being driven.

According to the present invention, there is provided an implement having a reciprocating driver with an electric motor for operating the driver. While the mechanism is particularly designed for use in driving tacks of this type, the 15 same mechanism for translating rotary motion into reciprocating motion and controllably striking a quick, hard blow may be adapted to other machines and devices requiring a similar action. With the present invention the rotary movement 2o of the motor shaft is translated into an oscillating or reciprocating movement of a pawl. The driver or impact tool is provided with a succession of teeth so that each stroke of the pawl serves to advance the driver the distance of one tooth in one 25 direction, and a detent or holding pawl restrains the driver from moving back after it has been so advanced. This advance is effected against pressure of a spring or other biasing means, a spring being the most compact form of biasing means.

When the driver has been moved a predetermined distance, there will be no further teeth for the motor-driven pawl to engage, and it will thereupon merely move back and forth without effecting any result. A trigger mechanism is provided 35 for releasing the holding pawl so that when the trigger is pulled, rendering the holding pawl ineffective, the spring or other biasing force will propel the driver at high speed and with great force in the opposite direction. Means are pro40 vided whereby after the trigger has been operated, it is ineffective to again release the driver until the driver has been completely restored to a cocked position, when the driver is again at the limit of its travel and the spring fully compressed.

&lt;5 The invention further provides a convenient form of tool for operating upon the T-tack strip above described and referred to in the former of my said prior applications, there being feeding ₆₀ means for advancing the strip automatically as each tack is driven. The invention provides in the particular embodiment shown, a compact, easily handled tool which is motor-driven, and which may be easily located with respect to the 55 work, and the tacks rapidly driven. The machine is so designed that the tacks may be well aimed, and damage to the finish of adjoining woodwork can be avoided, and less skill on the part of the operator is required.

The invention may be more fully understood

2,670,456 by reference to the accompanying drawings, in which:

Fig. 1 is a side elevation of a machine embodying my invention;

Fig. 2 is a view similar to Fig. 1, with part of the cover or casing removed, and with certain parts of the machine shown in section, the trigger being in the normal position and the mechanism being operative to cock the machine;

Fig. 3 is a machine similar to Fig. 2, just at the instant of releasing the trigger;

Fig. 4 is a longitudinal horizontal section in the plane of line IV—IV of Fig. 3;

Fig. 5 is a similar view in the plane of line V—V of Fig. 3;

Fig. 6 is a transverse vertical section through the strip feeder, the view being in substantially the plane of line VI—VI of Fig. 3;

Fig. 7 is a fragmentary transverse section in the plane of line VH—VH of Fig. 3;

Fig. 8 is a similar view in the plane of line VIII—VUI of Fig. 3;

Fig. 9 is a fragmentary view showing the driving nose of the machine with an attachment to limit the extent to which the tack is driven applied thereto;

Fig. 10 is an assembly view showing in side elevation one arrangement for using the driver and supplying it with fasteners from a strip carried on a reel suspended from an overhead trolley;

Fig. 11 is a detail view showing a counterbalancing arrangement for the organization shown in Fig. 10;

Fig. 12 is a side elevation of a slightly modified form of machine in which the reel of strip fasteners is positioned directly at the side of the machine;

Fig. 13 is a top plan view of a machine shown in Fig. 12;

Fig. 14 is a view similar to Fig. 13, with part of the construction shown in section; and

Fig. 15 shows a part of the strip guide for deflecting the fastener strip from the reel at the side of the machine into the feeding mechanism at the front of the machine.

Referring first to Fig. 1, the machine is generally patterned after a gun, having a pistol grip 2 with a trigger 3, and at the top of the pistol grip is a barrel portion 4. Forwardly of this is a casing S. The muzzle or driving nose from which the tacks are driven is designated 6, and the strip feeding machanism is designated generally as 7. The electric motor which is set into the casing 5 is designated generally as 8.

Referring now to Figs. 1 to 12 inclusive, the machine is preferably formed of two longitudinally divided sections or casings which are bolted or otherwise secured together in face-to-face relation, and which serve to hold and confine between them the various mechanisms to be hereinafter described, the arrangement being such that one of the two casing parts may be removed to give access to the mechanism.

The motor 8 runs continuously while the machine is in use. It has a worm gear 9 at the end of its armature shaft. An oiling pad 10 mounted on a bracket at the inner end of the motor bears against the worm wheel 9 to keep it lubricated, and a suitably located oil hole in the casing enables oil from a can to be dropped upon the pad for supplying lubrication to the pad. The worm gear meshes with a worm wheel 11 which is keyed to a transverse shaft 12 supported in bearings 13 at each side of the housing as best seen in Figs, δ and 7. This shaft has two eccentrics or cranks (4 thereon, which are both offset at the same angle, and to the same extent. Each crank is engaged by the inner end of a pawl member 15, the free ends of these pawl members being tied 5 together by a cross pin 16 (see Fig. 5). Each of these pawls is provided with a tooth 17 as clearly shown in Figs. 2 and 3. When the shaft 12 rotates, the cranks or eccentrics cause the two pawl elements 15 to move back and forth, and at the 10 same time they are free to move to a limited extent in an arc about the cranks as a center.

The driver, designated generally as 18, has an end 19 (see Fig. 3) which is adapted to shear the fastener from the end of the strip, propel it along 15 a guideway 20, and be discharged from the muzzle or nose 6. The driver also has a bending die portion 22, the formation of which is to engage the leg-forming element of the next-succeeding fastener blank of the strip and bend it down to a 20 perpendicular position. This enables the fastener strip to remain flat until immediately before the driving operation. As the driver completes its stroke in the driving of one staple, the die portion 22 cooperating with die block 22a operates to 25 engage the leg portion of the next succeeding blank and bend it. The exact arrangement by means of which this may be accomplished is more fully shown and described in my copending application Serial No. 634,537, filed December 12, 30 1945.

The driver 18 has secured thereon an inclined cam element 23, the purpose of which is to engage a roller 24 on a slide plate 25, which as viewed in Fig. 3 moves up and down, as contrasted 35 to the back and forth movement of the driver itself. The slide plate 25 is pushed down by the action of the cam 23 engaging the roller 24. It is pulled up in the opposite direction by a pair of tension springs 26 secured to post 27 on the slide 40 plate, and secured to fixed post 28 on one of the plates constituting the housing for the machine. The feeding mechanism illustrated is disclosed in my copending application last referred to. The slide plate which in Fig. 3 is shown in its upper45 most position, and in Fig. 2 is shown in its lowermost position, has spring-pressed pawls 29 thereon which engage in notches 30 in the edge of the fastener strip 31 that is fed upwardly through a narrow slot or channel 32 provided for it in the 50 machine. As shown, these pawls are tooth-like elements carried on resilient leaf springs 29a secured to the slide plate, the pawls passing through the plate and being movable in a direction normal to the plane of the plate. Two fixed holding 55 pawls 33 also engage in the notches 30 to prevent the strip from moving backwardly, once it has been advanced. The holding pawls are similarly carried on leaf spring arms 33a, all as more fully described in my said copending application Serial 60 No. 634,537.

Briefly, when the driver moves from the position shown in Fig. 3 to the position shown in Fig. 2, the cam 23 operating against the roller 24 pushes the slide plate 25 down against the 65 tension of the springs 26. During this time the pawls 33 lock the strip 31 against reverse movement, while the pawls 29 slide down along the edge of the strip. When the driver reacts to allow the slide plate to move up under the in70 fluence of the springs 26, the pawls 29, catching the notches 30 of the strip 31, cause the strip to travel upwardly with the upward movement of the slide plate. The disposition of the pawls and the maimer in which they engage in the 75 edges of the fastener strip is perhaps most

0,676,466 β

clearly shown in Fig. 6. while the general organization of the slide plate and its relation to the cam 23 is best shown in Figs. 2 and 3.

The driver II also has a rod 31 projecting axially from the top thereof, and the right-hand 5 end of this rod as viewed in Figs. 3 and 4 is slideably guided in a bore 31 in a barrel or guide block 37 that is threaded into the casing above the handle or grip 2 Of the machine, this barrel or block having a tubular extension 37a which 10 extends down toward the driver. A compression spring 38 is confined between the end of the driver II and the shoulder 31b formed between the tubular portion 31a, the guide block and the main body 31 of the guide block. This 15 organization is most clearly shown in Fig. 4.

Two racks 40 (see Fig. 4) are secured to the driver 18, one of them being at each side of the guide rod 31. These rack bars 4· have a succession of ratchet-shaped rack teeth 40a thereon. 20 These rack teeth are arranged for cooperation with the tooth elements II on the reciprocating pawls IS. Two pawls (I and two parallel ratchet bars or racks 41 are used to give symmetry to the design and avoid uneven distribution of forces 25 and loads, but obviously a single pawl and rack bar may be used.

As shown in Fig. 2, the pawl teeth II engage in the ratchet teeth 41a, and the throw of the cranks on the shaft 12 is such that each stroke 30 of the pawls is designed to advance the driver one notch or tooth toward the right, as viewed in Figs. 2 and 3, and effect a compression of the spring 38.

A transversely extending block 42, spanning 35 the distance between the two plates to the right of the path of travel of the reciprocating or oscillating pawl levers 15 as viewed in Figs. 2 and 3, supports a vertically slideable pawl element 43 (see Figs. 2, 3, 5 and 8), there being springs 44 for urging this element upwardly. It has two teeth 45 thereon, which are best shown in Fig. 8, and which teeth are adapted to normally be projected by the springs 44 into engagement with the ratchet teeth 41a of the ratchet racks 40. Thus as each throw of the pawls 15—II advances the racks one tooth, the pawl teeth 45 engaging the racks to lock the racks against reverse travel.

As best shown in Fig. 5, the block 42 has a rearwardly projecting extension 42a of reduced thickness forming a supporting bracket on which are mounted two pins 45. Positioned alongside the bradket 42 is a plate 48 which has inclined slots 41 therein (see Figs. 2 and 3) through which the pins 46 pass. A tension spring 49 anchored to one of the pins 46 and to a pin 50 on the plate 41 exerts a force tending to move the plate 48 upwardly and toward the left as viewed in Fig. 2. The plate 40 has a rearwardly extending projection 43a in which is a transverse pin 51. This pin is received in a slot 52 in. the upper end of a trigger lever 53 in the butt of handle 2 of the tool, the trigger 3 being formed on the lever 53 and projecting through an opening in the handle 2 near the top of the handle.

The plate 48 also has a narrow extension 48b thereon which passes over the middle of the pawl element 43 between its two teeth 45, as clearly shown in Fig. 5, and as shown in Figs. 5 and 8 it has little angles 41c welded to each side of it, the horizontal flanges of the angles being in the plane of the bottom of the extension 43b, and serving to increase the bearing area of the β

part 48b on the holding pawl 43 between its two teeth 45. This extension, with its little angles 40c, also passes over the cross pin 18 that joins the free ends of the two motor-driven pawls IS (seeFig.5).

Assuming the parts to be in the normal position shown in Fig. 2, but with the driver retracted to the cocked position shown in Fig. 3, the operator may press on the trigger 3, swinging the lever 53 toward the right as viewed in Fig. 3. This exerts a pull on the plate 48, the motion being transmitted through pin 51 in slot 52. The pins 46 engaged in the slots 41 cause the plate 48 to move downwardly as it also moves toward the right from the position shown in Fig. 2 to the position shown in Fig. 3. The downward movement of the plate 48 causes the extension 48b at the front of this plate to push down on the holding pawl assembly 43, disengaging its teeth 45 from the rack teeth 40a. It also presses down on the cross pin 16, moving the pawl teeth on the pawl 15 out of the line of travel of the rack teeth 40a. When this happens, there is nothing to hold the driver in the cocked position, and the spring 38 propels the driver with great force toward the left as viewed ih Fig. 3, to the position shown in Fig. 2.

The plate 48, as shown in Figs. 5. 7 and 8, has an angle 48d welded to one face thereof to provide ah overhanging lip or flange. One of the two arms 40 having the ratchet rack teeth 40a is provided as shown in Figs. 7 and 8 with a laterally extending tongue 54. When the driver is in the position shown in Fig. 2, this lug or tongue 54 is clear of the left-hand end of the flange 48d and when the driver is cocked and in the position shown in Fig. 3, this tongue 54 is clear of the right-hand end of the flange 48d. As the driver travels on its impact stroke from 40 the position shown in Fig. 3 toward the left, to the position shown in Fig. 2, the tongue 54 rides over the top of the flange 48d and even though pressure on the trigger is released, the spring 49 cannot operate to restore the plate 48 to its 45 raised position until the driver reaches the lefthand limit of its movement, when the tongue is again clear of the other end of the plate 48d. As soon as this happens, the plate 48 lifts and moves toward the left under the action of spring 50 49 to the position shown in Fig. 2, taking pressure off the holding ratchet assembly 43—45, and also off the pin 16 which depresses the two operating pawls. Thereupon the operating pawls . may again engage the ratchet teeth 40a to re55 cock the driver. As soon as the driver starts to move toward the right in being cocked, the tongue 54 will be under the ledge or lip 48d as shown in Figs. 7 and 8, and even though pressure is put on the trigger to pull it, the tongue 60 operating on the under face of the flange 48d will support the plate 48 and prevent it from being pulled down.

By reason of the relation of the tongue 54 and the flange 48d, a mechanism is provided where65 by it is impossible to operate the trigger at any intermediate position in the travel of the driver. This is important first to avoid prematurely and only partially advancing the feeder, secondly to avoid striking the tacks with insufficient force, and thirdly, to prevent the operator from repeating the driving of a tack by unconsciously pulling the trigger before he has the “gun” properly shifted and positioned at the next place where a tack is to be placed.

A bifurcated or wishbone-like stamping of

2,570,455 sheet metal designated 55 in Figs. 2 and 3 has its two arms secured to the under edges of the operating pawls 15, while the single opposite end of the stamping designated 55a is attached to one end of a tension spring 56, the other end of this spring being anchored to a pin 57 in the casing of the machine. This spring does not interfere with the back and forth movement of the operating pawls as effected by the cam shaft, but it does exert an upward thrust tending to resiliently raise the ends of these pawls to an operating position, except when they are depressed by the operation of the trigger mechanism as hereinbefore described.

Reviewing the operation of the machine, start- ,. ing with the parts as shown in Fig. 2, and with the motor operating, the motor turns the worm wheel 11 to rotate the shaft 12, reciprocating the pawls 15 so that their teeth 17 advance the racks 40a one notch at a time against the compression of the spring 38 until the driver has been moved to a position where the teeth of the rack are clear of the teeth 17 of the operating pawls. During this step-by-step advancing movement of the driver toward its cocked position, the holding pawl assembly 43—45 is effective to prevent the driver from moving in the reverse direction and the flange 48d riding over the tongue 54 prevents the trigger from being operated to prematurely release the driver. As the driver nears the end of its stroke, the springs 26 operate to advance the slide plate 25, whereupon the pawls 29 advance the fastener strip from the position shown in Fig. 2 to the position shown in Fig. 3, where the previously formed fastener is now directly in the path of travel of the driver.

When the trigger is pulled, the plate 48 is moved down and toward the right, and the extension 48b at its lower end simultaneously depressed the holding cam 43—45, and by pressure against the pin 16, moves the teeth 17 on the pawl arms 15 out of the path of travel of the racks so that the fully compressed spring 38 may then operate to move the driver toward the left, hitting the tack a sharp, quick blow, and driving it. Of course the first step in the driving is to shear the formed tack from the end of the strip. In this movement of the driver toward the left in driving the tack, the cam 23 engaging the roller 24 on the slide plate 25 moves the slide plate down from the position shown in Fig. 3 to the position shown in Fig. 2, so as to be ready to advance the fastener strip when the driver is next retracted. The shoulder 22 on the driver cooperating with a die block 22a near the nose of the machine operates to turn down the leg of the next succeeding tack blank as the tack in the guideway is being driven. As previously stated, this feeder and leg-bending arrangement is fully shown in my said copending application, Serial No. 634,537.

The invention provides a tool wherein a continuously operating motor of relatively small power can be used to move a driver by a succession of rapid small increments from an uncocked to a cocked position against the resistance of a spring. Because of the small increments of movement and the reduction of speed and the leverages of the cranks, the work done by the motor on each revolution is relatively small, so that while the spring may ultimately exert a pressure in the neighborhood of 150 pounds in the particular machine shown, the motor is not overloaded or stalled in cocking

8i the driver. The invention further provides a fool-proof trigger arrangement for a tool of this kind, whereby advancing of the tool or injury to the operating parts is prevented through the interlocking arrangement on the driver and trigger plate 48 that prevents the operation of the trigger and the movement of the trigger plate, except at the two limits of movement of the driver.

The invention further, provides a machine of unique design in which a compact motor-driven tool is provided for successively driving tacks formed from a strip of previously prepared metal. Because of the small area of the driver and the shape of the nose, tacks can be driven into corners and other places which are difficult to reach, even in hand tacking operations, and likelihood of damage to the woodwork is avoided, as for example in the application of tacks in upholstered furniture.

For aiding and' guiding the fastener while it is being driven, it will be noted by reference to Fig. 3, that there is a narrow channel 60 in one of the two plates forming the guideway.· to receive the leg of the fastener while the head of the fastener rides on surfaces 60a and 60b. A spring-pressed guide element 61 having a leaf spring 62 is provided through an opening 63 (see Fig. 4) into the tack guide. It normally exerts pressure against the upper edge of the leg which is the edge viewed in Fig. 3 at about the time the fastener is being driven, but it is cammed upwardly out of the path of travel of the head as the head of the fastener moves under, it. Thus at the instant the fastener begins to penetrate the material into which it is being driven, the leg is supported on all four sides against deflection.

Sometimes in the upholstering industry, it is desirable to only partly drive a tack so that it can be easily removed at a later period in the operation, or the driving-completed at a later time. To effect this with the..present machine, the attachment shown in Fig. 9 may be employed. This consists of a shell 65 shaped to fit over the· delivery end of the muzzle of the tool, and it has· a spring clip 66 adapted to snap into a recess in the nose of the tool to releasably hold· the casing in place. The end of the .driver never projects beyond the end of the nose. Therefore the shell 65 forms a spacer to keep the nose of the. driver away from the work so that the tack will be: only partly driven.

Figs. 10 and 11 illustrate one arrangement· for using the talking tool. In this arrangement, a bail 70 is attached-to a gun as shown in Fig. 10, and it is curved to provide a loop at 70a and it is bowed outwardly to provide another· slide loop at 70b. There is an eye 71 slideable on this bail, and it is connected' with a cord 72 hung from a spring roller 73 similar to a spring sash cord roller. ·. Normally the gun hangs pointed down, as shown in Fig. 10, but by manipulating it so that the eye 71 is in the loop 70b; the gun will then hang ini a normally substantially horizontal position! where it can be tilted to any angle. The roller 73 is hung' from a. bracket 74 which in tunrhas a hanger 75 suspended from a cable 76. The cable 76 fastens over a pulley'Π, another pulley 78, and has a counter-: weight 79 at its opposite end. The pulley 77 is hung from a trolley 80, movable along an overhead trackway 81.

The hanger 75^: extending upwardly from the bracket 74 has a reel 82 thereon to support

2,575,456 a roll of prepared fastener blanks 83. There is a guide tube 84 attached to the bracket 74, this guide tube having a flexible section 85 and an angle portion 86 that terminate adjacent the feeding slot of the gun. The electric supply cable is designated 87. This arrangement of the guide tube enables the strip of fasteners to be guided into the gun no matter at what angle the gun is being used, and avoids any kinking or bending of the strip from the time it unrolls from the reel until it enters the feed slot of the gun. The cable 72 and spring roller 73 take up the slack which exists when the gun is shifted from a horizontal position to the vertical position shown in Fig. 10, while the counterweight 79 counterbalances the up and down movement of the whole assembly as the operator raises and lowers the gun to work at different elevations. The trolley 80 and track 81 allows the operator to move along with the piece of work in which he is engaged in driving tacks. The counterbalancing arrangement relieves the operator of supporting much weight in using the tool so that he can very easily change its position and his arms do not become tired in using it.

In some cases it may be desirable to have the reel of the fastener forming blanks attached directly to the side of the machine instead of using the arrangement shown in Figs. 12, 13, 14 and 15. Nevertheless, even with this form of construction it is desirable to use a bail such as the bail 70 of Fig. 10 for suspending the machine to keep it from being dropped, although this bail has not been shown in Figs. 12, 13, 14 and 15.

The driver itself is of the same construction as that previously described, and is designated generally as A, and no reference will be made to the individual parts except as may be necessary for the purpose of understanding the present modification. One of the side plates of the machine A is provided with a supporting bracket 90 having an angular flange 91. The web 92 of a reel 93 is pivotally supported at its center by a pin 94 on the bracket 90 passing through the web of the reel and retained in place by a thumb screw 95. The reel 93 has a peripheral flange 93a that fits over the flange 91 of the bracket, the arrangement enabling the reel to rotate freely. At one point on its periphery, as best shown in Figs. 12 and 15, the bracket is provided with an axially offset spiralled portion 96, through which the strip is guided, as it unwinds from the periphery of the reel to appoint in alignment with the beginning of the strip-feeding slot designated 97 in the tacking machine, and which is similar to the guide previously described in connection with Figs. 1 to 10 inclusive.

With this arrangement the previously prepared reel of fastener blanks is merely put in position on the bracket, threaded into the machine, and as the strip is fed into the machine with the fasteners being consumed, the reel turns on the bracket. When the reel is exhausted, a new reel is substituted for it.

It may be noted that the casing is divided longitudinally into two sections, a cover section and a supporting section which carries all of the operating mechanism, the cover section having only a bearing for one end of the crank shaft. With this arrangement the cover may be removed without disturbing the operating mechanism.

While I have illustrated and described one particular embodiment of an impact tool designed in accordance with my invention, and one particular form of tacker, it will be understood that this is by way of illustration, and that various 5 changes and modifications may be made within the contemplation of my invention and under the scope of the following claims.