US3523441A - Blind rivet air tool - Google Patents

Description

2 sheets-sheet 1 mvmToRS W. BELL ETAL BLIND RIVET AIR TOOL Aug. 1l, 1970 Filed May lO, 1968 lgll 1970 f W. BELL ETAL 3,523,441

BLIND RvETAIR TOOL Filed May l0. 1968 2 Sheets-Sheet 2 ATTORNEY United States Patent O 3,523,441 BLIND RIVET AIR TOOL Walter Bell, Monroe, Zdzislaw Richard Kurc, Cornwall,

and George L. Timm, Highland Mills, N.Y., assignors to Star Expansion Industries Corporation, Mountainville, N.Y., a corporation of Delaware Filed May 10, 1968, Ser. No. 728,204 Int. Cl. B21d 9/05 U.S. Cl. 72-391 8 Claims ABSTRACT OF THE DISCLOSURE An improvement in a rivet setting tool which is pneumatically operated wherein the pneumatic means is operable to retain rivets in position and to eject the severed rivet mandrel stems therefrom automatically utilizing a common source of pneumatic power, which improvement resides ina new and unique trigger for the tool which permits ejection of rivet mandrels and air out of the device only when the trigger is at least slightly depressed, said trigger being the same trigger which operates the rivet pulling means of the rivet setting tool.

BACKGROUND `OF THE INVENTION Field of the invention This invention resides in the eld of pneumatic power operated rivet setting tools particularly adapted for the setting of blind rivet assemblies of the type wherein the rivet barrel is set in a workpiece by the tensioning of a mandrel stem having an enlarged rivet setting head engageable with the blind end of the rivet barrel. Further, this tool can be eifectively employed for the tensioning of a mandrel in a rivet assembly wherein upon completion of the rivet setting operation the mandrel stern is designed to sever or break as a result of the tensioning stress applied by the setting tool.

Discussion of the prior art Pneumatically operated power tools for upsetting, power tools are generally and broadly known in the art. Recently, a blind rivet setting tool which is pneumatically operated has been proposed which is provided with means for pulling and thereby severing rivet mandrels and with means for ejecting the severed mandrels automatically using a common pneumatic power source. The mandrels are ejected due to creation of at least a partial vacuum. When the tool is operated, valve means are provided to direct incoming air "into a number of cylinder units employed for severing the rivet mandrel. A direct passage carries air constantly toward the rearward portion of the tool to create the vacuum. This means that air is constantly passing through the device and out the rearward exit even when the rivet pulling operation is not being performed. This is undesirable for reasons of noise and the like. It is desired to perform the rivet mandrel severing operation at the same time or as close to the same time as the rivet ejecting operation and to limit the ejection of rivet mandrels and air to a time in which the main rivet setting function is being performed.

'SUMMARY `OF THE INVENTION Objects of the invention It is an object of this invention, therefore, to provide a rivet setting tool which functions to sever rivet mandrels thereby setting the rivet and to eject the severed mandrel from the tool which functions are performed using a common source of pneumatic power wherein the rivet ejecting function and any air used therefore is prohibited from being emitted from said tool at any time other than 3,523,441 Patented Aug. 11, 1970 ICC between commencement and termination of the rivet severing function.

This and other objects and advantages will become apparent from the following description and claims.

STATEMENT OF THE INVENTION Broadly, this invention contemplates an improvement in a blind rivet setting tool which is pneumatically operated, said tool operable to set rivets by severing rivet mandrels and to eject the severed mandrel from said tool using a common source of pneumatic power, said tool provided with means of directing incoming air toward a cylinder assembly and means for directing incoming air toward the rearward portion of said tool and into a Venturi passage and out of said tool whereby the vacuum created due to passage of said air out of said tool causes severed j mandrels to be ejected out of said tool, said improvement comprising a trigger operable to operate a valve in the power air line and a valve in an ejecting air line.

In a particularly desirable embodiment, the invention contemplates such an improvement wherein the trigger 0perates to open the valve in the ejecting air line prior to opening the valve in the power air line and, preferably, holds the valve in the ejecting air line open after the valve in the power air line is closed.

BRIEF DESCRIPTION OF THE DRAWINGS The invention can be more readily understood and appreciated by reference to the accompanying drawings in which:

FIG. 1 is a sectional view partly broken away showing the tool in the extended, normal, at rest position and a rivet disposed therein;

FIG. 2 is a front elevational view of the tool partly broken away;

FIG. 3 is a sectional view taken along line 3 3 of FIG. 2;

FIG. 4 is a sectional view taken along line 4 4 of FIG. 2;

FIG. 5 is a rear elevational view of the tool showing the deflecting boot in section;

FIG. 6 is a sectional view taken along line 6 6 of FIG. 5;

FIG. 7 is a sectional FIG. 5; and

FIG. 8 is a sectional view taken along line 8 8 of FIG. l.

lview taken along line 7 7 or DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings and in particular to FIG. 1, the rivet pulling tool therein illustrated is provided with a rivet engaging and pulling assembly, indicated in general by the numeral 22, a cylinder assembly, indicated in general by the arrow 20, within which is housed the pneumatic motor mechanism to provide the requisite reciprocative linear motion for the operation of the pulling assembly; and a handle portion 24 providing the requisite means for connecting the tool to a source of compressed air as well as constituting a support for trigger operated valve 94 means for controlling the operation of the tool.

-In FIG. l there is shown a pair of workpieces A and B, such as metal plates each having a drilled opening into which a rivet body C to be set has been inserted. The mandrel portion D of the rivet assembly is then inserted into the nosepiece of the pulling head assembly until the anvil throat 26 of the nose piece is in rm contact with the flanged portion of the rivet body. The pulling head assembly 22 is of well known type in its operation. The following brief description will sutiice to explain the cooperative interrelation of the pulling head assembly with the rest of the tool.

PULLING HEAD ASSEMBLY The pulling head assembly 22 is of a hollow tubular construction and includes a tubular housing 28 having a bore 30 within which a jaw case or retainer 32 is slidably mounted for axial reciprocation. Three toothed jaw members 34 are cooperatively arranged in a circle within jaws retainer 32, so that forward pressure of the jaws against the inner end 36 of the nosepiece 26 will force the jaws apart to receive or release the mandrel stem D. The separation of the jaws is additionally accomplished by the tubular jaw expander 38, the forward or proximal end of which is provided with beveled surfaces which are in camming engagement with the complementary surfaces of the rear end surfaces of the jaw members, thereby forcing the jaw members apart under the resilient action of the compression spring `40. It will be noted that the bore 42 forms a continuation of the mandrel receiving bore defined by the juxtaposed faces of the jaw members. Rearward retractive movement of the jaws retainer 32 causes the jaws to grip and to tension the mandrel stem D as the jaws are moved rearwardly toward the remote end of the tool.

In this connection it will be noted that the anvil throat end of the nosepiece 26 forms an abutment means for the flanged end of the rivet body. It will be further noted that the jaw case or retainer 32 is provided with a bore having a tapered or frusto-conical forward portion. The jaw members 34 taper in a forward direction in a manner complementary to the frusto-conical surface defined by the bore of the jaw retainer 32. The retainer and jaws held thereby are power-operated rearwardly by means of draw barrel 44 which is in threaded engagement with the jaws retainer 32. The draw barrel 44 in turn forms part of a pneumatically operated piston assembly to be hereinafter described. It will be noted at this point that the forward or proximal end 46 of the draw barrel 44 is enlarged and is slidably journaled in housing 28 and bears against the sealing O-ring `48 which provides an air seal therefor during the reciprocation thereof. The bore 50 extending throughout the length of the draw barrel is coaxial with the bores defined by the jaws 34 and the tubular jaws expander 38 and forms a continuation thereof.

PISTON HEAD ASSEMBLY The draw barrel 44 is provided with a shoulder 52 from which a reduced diameter piston rod portion 54 extends rearwardly and effectively supports a plurality of circular piston heads 56a, b and c. The piston heads 56a, b and c are provided with a central bore 58. The piston heads are similar in construction and are equidistantly spaced along said piston rod portion 54 of the draw barrel 44 by means of intermediate spacer bushings 60.

The remote or rear end of the piston rod portion 54 of the draw barrel is threaded and mounts a clamping nut 62. A washer `62a is interposed between the nut 62 and the raised boss formed on the rear face of the piston head 56C surrounding the bore 58. As a consequence of this arrangement the tightening of the nut 62 effectively clamps the piston heads 56a, b and c in position and thus forms a unitary piston assembly comprised of the draw barrel and the piston heads mounted thereon. It will be noted that the draw barrel is provided with a liner 64 which includes a funnel shaped forward portion at its forward end and a tail portion 66 which extends beyond the draw barrel y44. The opening of the funnel is reinforced against end 46 by reinforcing material 64a.

CYLINDER ASSEMBLY The piston assembly is disposed within the cylinder assembly of the tool for reciprocative movement therein. The cylinder assembly is comprised of a front cylinder unit designated generally by the numeral 68, a rear end plate designated generally by the numeral 70, and intermediate cylinder units designated generally by the numerals 72 and 72a. It will be understood, as will more clearly appear hereafter, that the end plate 70 may be mounted directly upon the front cylinder unit 68 or one or more intermediate cylinders may be interposed therebetween in accordance with the power requirements of the particular application. As will be seen from said FIG. l, the front cylinder unit 68 is comprised of a cylinder shell portion having an integrally formed handle portion 24 depending therefrom. The cylinder head 74 of front cylinder unit is provided with a threaded central bore 76 within which the tubular housing 28 of the rivet engaging and pullling assembly 22 is received so as to threadedly mount the same. A plurality of circumferentially spaced apertured ears 78 are provided on the external surface of the unit for receiving the clamping bolts `80. The cylinder shell of the front cylinder unit has disposed therein piston head 56a of the pis` ton assembly for reciprocation therein under pneumatic pressure. In order to provide for an air seal an O-ring 82 is disposed within a circumferential groove found in each of the piston heads 56a, b and c and comprises a piston ring therefor.

It will be noted that in the at rest or normal position of the tool the front face of the piston head abuts the raised boss `84 formed on the interior face of the front cylinder head 74 and that a circular depressed area surrounds said boss. There is thus formed a pocket 86 into which compressed air may be introduced to initiate the power stroke of the tool as will more particularly appear hereinafter.

The front cylinder unit 68 is also provided with conduit means for connection to a source of compressed air supply and for introducing the same at the desired locations in the tool. Thus the handle portion 24 has formed therein an air inlet conduit 88 which is provided with a threaded mouth 90 suitable for connection to the coupling element of an air supply hose and an exhaust conduit 90a through whlch the spent compressed air from the cylinders may be exhausted.

As may be seen from FIGS. 1 and 4, the handle also has formed therein as by means of suitably drilling the same through the body of the unit and plugging the undesired openmgs, a plurality of air passages. Since, after the initial lntroduction of air into the front cylinder unit the ow is utilized .for two independent purposes, namely, for providmg a1r power to the cylinders on the one hand, and for producmg a vacuum by means of a Venturi arrangement, the air or passages for the former will be designated as power air and passages, while the air or passages for the latter will be designated as Venturi air or passages.

Thus air introduced into the air inlet conduit passes into the rear portion of a valve chamber as indicated 92 and thence into the body of a cartridge valve 94 disposed within a portion of said chamber. Cartridge valve 94 controls the flow of power air and is of conventional design and will not be described in detail. The Valve 94 is operated by means of a reciprocable trigger or plunger 96 which is provided with a hemispherical end 98 which bears against the valve end. The movement of the trigger is limited by means of a cross-pin 21 which is disposed within a larger diameter transverse bore 23 formed in the body of the trigger. This same trigger is operative to open and close the valve in the Venturi air passage as more fully described below. When the trigger is depressed, power air from chamber 92 is permitted to pass through the valve into the opening 25 of power passage 27. Power passage 27 is diagonally disposed within the handle body and extends into the cylinder portion of the front cylinder unit. As may be seen from FIG. 1, power passage 27 traverses the juncture of the front cylinder head 74 with the cylinder wall 29 to thus form a power air port into the interior of the front cylinder. It will be noted that the port opens into the depressed area of the interior of the cylinder head.

It will also be noted that power passage 27 also intersects an axially extending power passage, not shown, which passage is open at the rear face of the cylinder wall 37. It will thus be apparent that compressed air introduced through conduit 88 is passed into the front cylinder under the control of a manually operable valve and is then conducted into the cylinder proper and that a further power air passage is provided in the cylinder wall for feeding power air into the next adjacent cylinders in the same manner, a power passage 27a, 27b or conduit provided therefor and at each cylinder head an air inlet so as to enable cylinder units 72 and 72a to act similarly. The power passages 27, 27a, 27 b are also utilized for exhausting spent air from the cylinders on the return stroke of the pistons. The return stroke of the pistons is initiated by the release of finger pressure upon trigger 96 which permits the cartridge valve to return to its normal position shutting off communication between the opening 25 of passage 27 and the rear portion of valve chamber 98. The valve simultaneously opens communication between the opening 25 of passage 27 and the reduced portion 37 of exhaust conduit 90, the bottom of which is open to the atmosphere. The spent power air may thus pass through exhaust conduit 90a via the aforementioned passages.

The vacuum forming Venturi arrangement requires a source of compressed air which is introduced through opening 39 as may be seen in FIGS. 1 and 3 and more particularly in FIGS. 4, 6 and 8. Opening 39 communicates with diagonally extending Venturi air passage 41 which in turn intersects and therefore communicates with axially extending Venturi air passage 43 disposed in the front cylinder wall and is open at the rear face of cylinder wall 37 as indicated at 45, so that it Will provide for a flow of Venturi air to the next adjacent cylinder. It will be noted that the axially extending power passage for the cylinders which is not visible in the drawings and passage 43 is disposed in parallel relation along opposing sides of the bore within which a clamping bolt 80 is disposed. i

The intermediate cylinder unit is also provided with air passage means Iwhereby it is connected to the source of air power for actuating the piston disposed therein. Thus, an axially disposed power air passage extends from face to face of the cylinder wall in registry with the power air passage which runs parallel to passage 43. A short diagonal bore 27a and 27b at the convergence of the interior ofthe cylinder head with the side wall provides communication with the exterior of the cylinder in the recessed area of the cylinder head without interfering with the continuity of the power air passage employed so that the next adjacent unit can be supplied therethrough. It will be apparent that when the intermediate cylinder unit is brought into clamping engagement with the cylinder head, a power air supply passage therefor is automatically established as well as with a next succeeding unit, if needed. The aforementioned power air passage also functions as an exhaust passage for the spent air upon the return stroke of the piston. In like manner, the intermediate cylinder unit when clamped in position automatically forms part of a continuous passage for the supply of air to the Venturi or vacuum arrangement. Thus there is provided a through passage which registers with the opening 45 of Venturi air passage 43 of the front cylinder head unit thus forming a continuity thereof for supplying the desired air to the ultimate point of application.

As heretofore stated intermediate cylinder unit 72a is in all respects similar in construction to unit 72 and serves to illustrate the modular character of the instant invention. Any desired number of intermediate cylinder units may be assembled and interposed between the front cylinder unit and the end plate assembly depending upon the power requirements of the particular application. With the addition of intermediate power units an increase in effective power of the tool is readily accomplished. It will of course be understood that a change in the number of intermediate cylinder units also involves a change in the piston assembly to accommodate the same.

END PLATE ASSEMBLY The tool is enclosed by means of an end plate assembly designated generally by the numeral 70. The said end plate assembly may be more particularly seen from FIGS. 1 and 5. It comprises an end wall 61 which is of the same general conformation as the cylindrical shell portions of the front and intermediate cylinder units. It is similarly provided with a circumferential recess 63 which receives the end of the preceding cylinder wall. Registering, circumferentially spaced apertured ears 78 are adapted to receive the ends of the clamping bolts 80 so that it may be assembled therewith and clamped thereto to form a unitary structure. The clamping action is accomplished by means of the nuts 65 in engagement with the threaded ends of the clamping bolts 80. The end wall portion 61 of the end plate is provided with a circular recess 67 within which a ring 69, formed of rubber or the like, is disposed. The ring 69 forms a bumper or shock absorbing pad for the piston head 56a as it abuts against the same upon reaching the limit of its rearward movement during the power stroke of the tool. A considerably deeper circular recess or groove 71 is formed in the neck portion 73 of the end plate and defines a sleeve 75 about which the return spring 77 is disposed. Said return spring 77 is of the compression type, one end of said spring abutting washer 62a and being disposed about nut 62 which thus prevents it from being dislocated, while the other end of said spring is seated at the bottom of groove 71 and is retained against dislocation by means of sleeve 75. Spring 77 is compressed during the retractive or power stroke of the tool and serves to return the piston assembly to its extended, normal or at rest position by reason of the resilient action thereof.

The neck portion 73 of the back plate 70 houses a Venturi type vacuum device which serves to retain a rivet disposed within the pulling head of the tool as it is manipulated into position with respect to a workpiece, and also serves to withdraw and eject the severed portion of the rivet mandrel from the tool proper. It is a significant feature of this invention that the vacuum forming means is integrated with the tool and is rendered operative by the same supply source of compressed air as is used to actuate the tool and that a common trigger is operative to operate the valves for the Venturi vacuum assembly and the power assembly.

The Venturi type vacuum forming arrangement is more particularly illustrated in FIGS. 1 and 8. As will be seen from said figures said arrangement designated generally by the numeral 79 is comprised of an outer tube 81 and an inner tube 83 disposed therein. Outer tube 81 is provided with a peripheral groove 85 into which a portion of a transverse locking pin 87 extends to lock the same in position with respect to the neck portion of the back plate as seen in FIGS. 5 and 6. Said outer tube wall is also provided with a recessed portion 89 having a triangular configuration in cross section. The tube wall defined by said recess is provided with spaced aperture 91 which provides air passage from the space defined by the recessed portion into the interiorof the outer tube.

The portion of the inner tube juxtaposed to said aperture 91 is of reduced diameter and provides a constructed circular orifice in conjunction with the interior wall of the outer tube thereby creating a Venturi effect in a well known manner. When a fiow of air is introduced into the interior of the Venturi arrangement in the manner indicated, the air is moved in the direction of the arrow E thereby inducing a pressure drop downstream of the air flow. In order to induce the vacuum downstream of the Venturi arrangement, means are provided for conducting a flow of air thereto. To this end the back plate is provided with a diagonal Venturi air passage 97 through web 101, the lower end of which is open at the front face of the end wall portion 61 of the end plate 70 and registers with a Venturi air passage from intermediate cylinder 72a. The upper end of Venturi air passage 97 tangentially opens into the bore of the end plate neck 73 into the space dened by the recessed portion 91 in the peripheral surface of the outer tube 81, from whence it may enter the interior of the Venturi tube arrangement through aperture 91 causing a vacuum to be created throughout the length of the axial bore defined throughout the length of the tool. The flow of air supplied to the Venturi may be regulated by means of a rotatable metering valve 99 interposed in passage 97. Rotation of the valve element causes the cross bore in the valve to register in varying degree with the passage and may thus be used to regulate the air flow or to shut it off completely. FIGS. 6 and 7 showing the valve in closed position, when rotated in the direction indicated by the arow in FIG. 7, alignment of the cross bore with the axis of the passage will open the same. A sealing arrangement is provided comprising of a pair of O-rings 99a which are held in position on each side of web 101 by means of push nuts so that the valve arm 103 may be rotated without leakage of air. This valve is provided so that the operator can choose if he wishes to use the ejecting device and, if not, close this valve.

A deecting boot 105 preferably formed of a hard rubber or the like is mounted on the neck of the end plate as by means of a rib and groove arrangement. The deflecting boot directs the severed mandrel stem away from the operator as indicated at F in FIG. l.

THE TRIGGER-VALVE MECHANISM The trigger-valve assembly is illustrated in FIGS. 1, 3 and 4. As seen therein, a plunger 96 is provided for operation of the cartridge valve above referred to. Embedded within plunger 96 in a recess 150 is a vertical portion 152 of the Venturi valve which portion bends and extends into the handle portion 24 horizontally at 154. A decreased diameter extension member 156 is provided around which is an O-ring 160 which sits between the end wall of the horizontal portion 154 and the wall 162 to which member 156 is attached. In the horizontal portion 168, small passage 164 permits air ow into Venturi pasage 45. At the end of the second horizontal portion 154 there is integral therewith piece 168 lling the bore 170. This entire assembly is rideable in the bore 170. Piece 168 lies in the path of Venturi passageway 41 when the tool is in rest. When the plunger 96 is actuated, the Venturi valve is pushed inwardly in bore 170 so that the passage 164 is in the path of Venturi passageway 41 and, air is permitted to Iflow through the valve into Venturi passage 45 and into the Venturi assembly to perform the exhausting or vacuuming operation wherein severed rivet stems are ejected from the tool.

It will be observed that this can be done without opening the power cartridge valve to begin setting rivets. This is due to the fact that the power valve is not immediately responsive to movement of the plunger 96 but requires movement of the plunger sufficient for the wall 172 to move sufliciently forward to open the power valve. Conversely, when the trigger is released slightly the power valve closes sufliciently to prevent air from going to the cylinders. Nevertheless, air can still pass through the Venturi valve as long as the plunger 96 remains slightly depressed. Thus, as long as the trigger 96 is not depressed, no air ows to the mandrel ejection device. When the operator depresses the trigger only slightly, say 1A; inch, air flows to the mandrel-ejection device. This ejects a mandrel, should there be one left in the tool, and also serves to hold in place a new rivet in the nosepiece of the tool. Depressing the trigger slightly further operates the original or power valve which in fturn releases air to the cylinders of the tool, and the rivet is installed in the work. The operator can release the trigger only slightly. The original or power valve is thus closed olf, and the cylinders return to their passive position, releasing the jaws from their grip on the brokenotf mandrel. The mandrel is ejected rearwardly from the tool and the operator releases the trigger fully and all air stops.

This assembly has the advantage that it decreases substantially the amount of high pressure air wasted and decreases the overall noise while providing the operator with full control of all functions through use of a single trigger.

In accordance with a preferred embodiment of the present invention as shown in the accompanying drawings, a two-position trigger is provided so that the operator has the option of choosing to have the rivet ejection system operated only when the rivet severing system is in operation i.e. so that the rivet ejecting system is not in operation unless the rivet severing system is operated. To this end, the side wall 172 of the cartridge valve at a point substantially intermediate, the ends of elongated slot 23 of elongated configuration is provided with an opening 231) of sufficient size to permit entry therein of pin 21. Generally speaking, the position of opening 23h is just rearward of the forward end of the elongated slot 23 and is correlated so that its distance between that point and a point on the vertical plane passing through the rearward end of the elongated slot 23 corresponds to the distance the trigger must be depressed to engage the rivet severing system. Thus by removing pin 21 and placing opening 23b in registry with the transverse bore and reinserting pin 21 into the transverse bore through opening 2311, the trigger is caused to operate fthe cartridge valve and the rivet ejecting valve concurrently, there being no give due to provision of an elongated slot which permits independent operation of the rivet ejecting system. To facilitate the change, a second opening 150b having the same shape as first opening 150 is provided so that when the assembly is turned the vertical portion 152 can be inserted in an appropriate recess. Thus it is seen that simply by removing pin 21 and turning plunger 96 including wall 172 and reinserting pin 21 through elongated slot 23 or 23b, the operator can choose whether the trigger mechanism is to operate the ejection system and the severing system together or whether the ejection system shall be engaged before the severing system. In the latter case, the pin 21 passes through the elongated slot 23 whereas the simple circular opening 23h is used in the first alternative.

It will be seen from the foregoing that a tool is provided which may utilize one or more cylinders for the pneumatic operation. The power applied to the mandrel stem Will be in direct proportion to the number of cylinders utilized. By the use of the valve and trigger mechanism shown and described, -additional advantages are realized within highly useful tools.

While certain preferred and desirable embodiments have been shown and described above, these have been shown and described merely for purposes of illustration and not for purposes of limitation, as there is no intention in the use of the terms and expressions employed herein of excluding any equivalents thereof, or portions thereof, within the spirit and scope of the invention.

'What is claimed is:

1. Au improvement in a blind rivet setting tool which is pneumatically operated, said tool operable to set rivets by severing rivet mandrels and to eject the Severed mandrel from said tool using a common source of pneumatic power, said tool provided with means for directing incoming air toward a cylinder assembly and means for directing incoming air toward the rearward portion of said tool and into a Venturi passage and out of said tool whereby the vacuum created due to passage of said air out of said tool causes severed mandrels to be ejected out of said tool, said improvement comprising a trigger operable to operate a valve in the power air line to said cylinder assembly and a valve in an ejecting air line.

2. An improvement according to claim 1 wherein said trigger operates to open the valve in said ejecting air line prior to opening the valve in said power air line.

3. An improvement according to claim Z wherein said trigger is operable to hold said valve in said ejecting air line in opened position after said valve in said power line is closed.

4. An improvement according to claim 1 wherein said valve in said power air line is a cartridge valve and said valve in said ejecting air line comprising a rod member movable in a bore in said tool and having a portion of decreased diameter whereby movement of said rod is registry with said ejecting air line permits air to pass through said valve.

5. An improvement according to claim 4 wherein said rod member is embedded with said trigger whereby lateral movement of said trigger moves said rod member and said cartridge valve is opened until said trigger has moved a predetermined distance.

6. An improvement according to claim 1 wherein said trigger is adaptable in a first position to operate to open the valve in said ejecting air line prior to opening the valve in said power air line and in a second position to operate the valve in said ejecting air line and the Valve in said power air line concurrently.

7. An improvement according to claim `6 wherein said trigger is adaptable in said second position to hold said value in said ejecting air line in opened position after said valve in said power line is closed.

8. An improvement according to claim 7 wherein the trigger comprises a plunger section and wall provided on its side with an elongated slot and along said wall a second opening just large enough to accommodate a pin passing therethrough, said second opening being between the extremities of the elongated slot and just rearward of the forward extremity, a transverse bore within an interior support portion of said trigger which bore can be in registry with said elongated slot and said second opening and held in registry by said pin, means within said plunger to accommodate means associated with said valve in said ejecting air line when said elongated slot is in registry with said transverse bore and when said second opening is in registry with said bore.

References Cited UNITED STATES PATENTS 2,088,859 S/1937 Huck 72-391 3,082,898 3/1963 Bosch 72-391 3,196,662 7/1965 Simmons 72--391 3,415,102 12/1968 Elliott 72-391 3,451,248 6/1969 Bell 72--391 CHARLES W. LANHAM, Primary Examiner G. P. CROSBY, Assistant Examiner U.S. Cl. X.R. 72-45 3

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