Washer Feeder For Nail Driver

Abstract

An automatic mechanism for feeding washers to a nail driver so that each nail will be driven through a washer, through the work and anchored.

Description

BACKGROUND AND FIELD OF INVENTION

Highly effective pneumatically operated fastener driving machines are available, the fasteners usually being in the form of staples. It is often desirable, however, in applying sheet-type built-up roofing, composition shingles, plastic films or tarpaulins and other such materials to employ washers with the fasteners in order to provide a large bearing surface which will hold the material more securely. Much of the advantage of a rapidly operating fastener driving machine is lost if the washers have to be placed manually. A need exists for a machine which will drive nails with washers with the same speed and convenience that is possible with staples.

SUMMARY of INVENTION

The present feeder is arranged to feed washers one after another to the driving position of a pneumatically operated nailing machine. The feeder is pneumatically operated from certain air passages in the nailing machine for automatic synchronization with the nailing machine whereby a washer is placed in position to receive a nail in each driving stroke of the driver blade of the machine. The washers are fed separately from the nails to eliminate any preliminary step of assembling the washers on the nails, and held in operative position by magnets or by air pressure.

BRIEF DESCRIPTION of DRAWINGS

FIG. 1 is a perspective view of the mailing machine embodying the features of the invention;

FIG. 2 is a perspective view of a nail and washer as driven by the machine, apart from the work;

FIG. 3 is an enlarged sectional view taken on the line 3-3 in FIG. 1;

FIG. 4 is a sectional view taken on the line 4-4 of FIG. 3;

FIG. 5 is a sectional view taken on the line 5-5 in FIG. 3;

FIG. 6 is a sectional view taken on the line 6-6 in FIG. 3;

FIG. 7 is a view similar to FIG. 5 showing a modification;

FIG. 8 is a sectional view taken on the line 8-8 in FIG. 7;

FIG. 9 is a view similar to FIG. 5 showing another modification;

FIG. 10 is a view of the machine shown in FIG. 1 with parts broken away, showing the trigger in actuated position; and

FIG. 11 is a fragmentary view similar to FIG. 10 showing the trigger in released position;

FIG. 12 is plan view of upper side of the soleplate;

FIG. 13 is a sectional view taken on line 13-13 of FIG. 12 with parts broken away for clarity.

DESCRIPTION OF PREFERRED EMBODIMENTS

In order to illustrate the application of the invention, a particular form of nail driver will first be described, but it is to be understood that the invention may be applied with equal facility to other nail drivers which are of generally similar form of construction. As shown in FIGS. 1 and 10, the present nail driver comprises a base magazine 10 having a hollow handle 11 equipped with an air inlet connection 12 for a compressed air hose (not shown). The magazine is equipped with a conventional spring feed device (not shown) to feed adhered "sticks" of nails N into driving position under a head portion 13 of the machine.

Integral with head portion 13 is a vertical driver cylinder 15 having an upper large diameter portion 16 and a lower small diameter portion 17. A spool-shaped piston 20 is mounted for reciprocation in the cylinder, the piston having a large head 21 in the large cylinder portion 16 and a smaller head 22 in the smaller cylinder portion 17. Connected to the lower end of piston 20 is a driver blade 19 for driving the nails N.

The hollow handle 11 contains an air reservoir chamber 23 and another chamber 24 of the reservoir is contained in head 13. These two reservoir chambers are parts of a common reservoir and are in constant communication with each other as well as with an air supply thru connection 12. A series of ports 25 communicate through the cylinder wall from chamber 24 into the space between the upper and lower piston heads 21 and 22. By reason of the slightly larger diameter of upper piston 21, the reservoir pressure thereby produces a constant upward bias on the piston, tending to retract and/or maintain blade 19 in its upper position.

The cylinder has a free upper edge 26 which is exposed around its entire periphery to the air pressure in a reservoir chamber 24. Mounted for reciprocation immediately above the edge 26 is a poppet valve 27 having a resilient sealing ring 28 arranged to engage said edge 26 of the cylinder end. Poppet valve 27 is incorporated in a piston 30 which is free to reciprocate in a short cylinder bore 31, the valve and piston being biased downward by a compression spring 32. The upper side of the piston is formed as a head stem 33 having a resilient seal ring 34 for sliding engagement in a bore 35. The piston contains an axial passage 36 which registers with an opening 37 in a cushion seat 38 in the upper end of bore 35. Registering with said bore and passage is a passage 39 communicating with a tapped opening 40 in the top of the head. A radial exhaust port 41 communicates with bore 35 just below the cushion seat 38.

The upper end of cylinder 31 has a port 45 which communicates with two different passages. One is a passage 46 extending to a tapped opening 47 in the top of the head and the other is a passage 48 communicating with a trigger valve assembly 50 in the handle. This assembly is made as a cylindrical unit which is mounted in an interior web or boss portion 51 of the handle extending through the reservoir chamber 23. Valve unit 50 and web 51 do not obstruct communication between the two reservoir chambers 23 and 24. The valve assembly contains a spool valve element 52 which is normally biased downward by a spring 53 and air pressure through a port 54, as shown in FIG. 11, to connect passage 48 with reservoir pressure. When the trigger 55 is raised (see FIG. 11), the valve spool is lifted to connect passage 48 with a discharge passage 56 as shown in FIG. 10.

When the trigger 55 is released as shown in FIG. 11, reservoir air pressure is transmitted through port 54 and passage 48 to the top of cylinder 31 to act on a large area of piston 30 and hold the poppet valve 27 closed against the top end 26 of cylinder 15. Reservoir pressure also exists around the upper end of the cylinder in reservoir chamber 24 and acts on a small area of piston 30. Piston 20 is normally held in its uppermost position by the action of reservoir pressure in the space between the upper and lower piston heads 21 and 22 as previously mentioned, i.e. being permitted to move upward because exhaust passage 36 is in communication with passage 41 to permit the air pressure to escape, since valve 30 is in "closed" position (down).

When the trigger 55 is raised as shown in FIG. 10, passage 48 is switched from supply port 54 to exhaust passage 56, allowing the air pressure above piston 30 to exhaust to atmosphere. The reservoir air pressure in annular chamber 24 around the cylinder 15 is effective on the under side of piston 30 to raise the piston and compress spring 32. This opens the upper end of cylinder 15 to reservoir pressure above the piston head 21, driving the piston 20 and driver blade 19 downward in a nail driving stroke. The upper end of stem 33 of piston 30 is then seated and sealed against cushion member 38 closing the exhaust port 41 and allowing reservoir air to also flow upwardly through passages 36 and 39 for operating the washer feeder as will presently be explained.

When the trigger is released, as in FIG. 11, air pressure is restored to passage 48 and the top of cylinder 31 to return the poppet valve 27 into sealing engagement with the upper end of cylinder 15. At the same time, the air pressure admitted through ports 25 in cylinder 15 raises the piston 20 in a return stroke, the air from the upper end of cylinder 15 being exhausted to atmosphere through passage 36 and exhaust port 41.

Thus, the passages 39 and 46 are alternately connected with pressure and exhaust. When the trigger is released, as shown in FIG. 11, passage 46 is connected with pressure and passage 39 is connected with exhaust, and when the trigger is raised, as shown in FIG. 10, passage 46 is connected with exhaust and passage 39 is connected with pressure. The tapped openings at 40 and 47 provide pipe connections to reciprocate a piston in the washer feeding mechanism synchronously with the operation of the nail driver as will now be described. Except for the passages 39 and 46 the tapped openings 40 and 47, the structure and operation thus far described are conventional.

The present washer feeder may be used with nail driving machines adapted to drive any conventional type of nail, such as round head or T-head, but in the illustrated embodiments, the nails N are of special L-shape having an angular head portion extending laterally in one direction from the shank. Such nails are conveniently and economically formed by cutting a stick of U-shaped staples in half through the middle of the crown. Each staple thereby forms two nails, the head of each nail being half the crown portion of the original staple. When one of these nails is driven through the aperture in a washer W, the head or half crown portion overlies the washer as shown in FIG. 2. With only slight modification of the machine, such nails are readily fed through the magazine 10 of a conventional staple driving machine whereby it becomes a nail driving machine. Although it is not necessary to use apertured washers it would be preferable. The nails will drive through unapertured discs if desired.

The washer feeding mechanism is mounted on a base plate 60 as shown in FIGS. 1 and 3. While such base plate may be incorporated as an integral part of the main casting of the nail driving machine, it is herein illustrated in the form of an attachment. Thus, the conventional guard plate of the nail driving machine is removed and base plate 60 is attached to the under side of base magazine 10 by screws 61, two of which appear in FIG. 5. Base plate 60 is hollowed out to provide cavities for the operating mechanism and the underside is enclosed by a shoe or soleplate 62 secured by screws 63. These two plates are separated by a flat marginal spacer plate 64 which is slightly thicker than the washer W for purposes which will presently appear. Preferably, the soleplate is tapered in thickness so that its bottom surface slopes upward at a small angle in longitudinal and lateral directions away from the nailing point as shown.

Base plate 60 extends laterally to one side of base magazine 10 to provide room for a cylinder block 65 and inclined washer feed tube 66 as shown in FIG. 1. The lower end of feed tube 66 is located alongside nail driver blade 19. The lowermost washer in feed tube 66 is held down flat against soleplate 62 by one or more magnets 67 as shown in FIG. 3. This places the bottom washer in the plane of spacer plate 64 which is cut away in this region. The feeder mechanism shown in FIGS. 3, 5 and 6 is adapted for use with washers of magnetic material.

Spacer plate 64 has a U-shaped cutout 70 providing a washer pocket facing toward the lowermost washer in the feed tube 66 and providing guide and positioning walls so that when the lowermost washer is shifted from its feed tube position at W in FIG. 5 by means to be described, the wall of cutout 70 will stop the lateral movement of the washer and position it accurately at W.sub.1 with its aperture in alignment with the shank of the next nail to be driven by driver blade 19. This location of the nail shank and washer aperture is indicated at N in FIG. 5.

The nail is driven through a vertical slot 71 in a nail guide 72 which projects through a circular opening 75 in base plate 60. Opening 75 is smaller than a washer. Underneath the washer W.sub.1 in nailing position, the soleplate 62 is provided with a circular opening 73 slightly larger than the washer to permit the washer to move through the soleplate against the nailing surface when the nail is driven. In this embodiment the washers are prevented from dropping through the opening 73 prematurely by a pair of magnets 74 which are contained in recesses in base plate 60 and have flat under surfaces flush with the underside of said base plate. See also FIG. 10. Thus, the bottom washer in feed tube 66 is first engaged on its under side by the magnets 67 and then as this washer is moved over the opening 73 to W.sub.1 position, it is engaged on its upper side by the magnets 74, this lateral sliding movement of the washer being in a passage in the plane of spacer plate 64 between base plate 60 and soleplate 62.

There also appears in the views in FIGS. 5 and 6 a safety plunger 77 which is arranged to prevent actuation of the poppet valve 27 until the plunger is depressed upwardly to the level of soleplate 62 so that the nail driving mechanism cannot be operated until the machine is applied in driving position to a working surface. Plunger rod 77 is arranged to lift exhaust valve 78 in FIG. 10 and open exhaust passage 56 to atmosphere. It should be apparent that the plunger could be set in a position level with the soleplate 66 if this safety feature is not needed.

In order to feed washers when the nail driver is held in different positions, the feed tube 66 is preferably provided with a cap 80 equipped with a compression spring 81 and a follower 82 to press the stack of washers toward the magnets 67.

FIGS. 7 and 9 show two different modifications for holding washers of nonmagnetic material such as plastic. As shown in FIGS. 7 and 8, such washers may be gripped by their edges between a pair of spring fingers 108 which are pivotally mounted on pins 109 in base plate 60 and urged together by a spring 110. These fingers have sloping gripping surfaces 115 which converge downwardly as shown in FIG. 8 to retain the washer. When the nail is driven, the fingers yield outwardly to release the washer through opening 73.

The modification shown in FIG. 9 more nearly resembles FIG. 5, suction apertures 100 in base plate 60 being substituted for the upper magnets 74. This arrangement is suitable for use where there is a convenient source of air suction available. When the nail is driven, the washer is pulled away from the suction apertures on the top side of the washer, allowing the washer to pass downwardly through soleplate opening 73.

The washer lateral feeding mechanism is the same for all embodiments as shown in FIGS. 3 and 5. The washer is shifted laterally from a position W at the lower end of tube 66 to a position W.sub.1 overlying opening 73 by a delivery arm 86 which is pivotally mounted at 87 on the base plate 60. The main portion of arm 86 is of slightly less thickness than a washer and moves in the plane of spacer plate 64 which is cut away to provide space for the arm. This arm has a rear end with an upward facing slot 88 (see FIG. 3) to receive a depending drive pin 89 in a piston 90. This piston is mounted for reciprocation in a bore 91 in cylinder block 65. The retract stroke of the piston is cushioned by a rubber bumper ring 92 and the feed stroke is cushioned by a rubber bumper ring 93 which seats against an adjustable plug 94 to accurately control the length of the feed stroke of delivery arm 86.

The feed stroke is produced by air received through an air pipe 95 connected with the opening 47 in FIG. 10 and the retract stroke is produced by air received through a pipe 96 from the center opening 40. The cylinder bore 91 may also be provided with a port 97 a short distance from the port for supply pipe 96. When thus provided, port 97 is connected with a pipe 98 leading to an opening 99 in the washer feed chamber as shown in FIG. 5. Then each time delivery arm 86 retracts, a momentary puff of air is delivered to opening 99 into the washer feed chamber to prevent the entrance of dirt and dust from the impact of the nail during its driving stroke.

When the driving mechanism is in normal rest position as shown in FIG. 11, there is a washer in driving position at W.sub.1 and delivery arm 86 is held advanced in its solid line position in FIG. 5 by air pressure in passage 48 and pipe 95 to hold the washer firmly in pocket 70. Then when trigger 55 is actuated to its FIG. 10 position, pipe 95 is exhausted to atmosphere through passages 48 and 56 and air pressure is applied to pipe 96 through passages 36 and 39, retracting piston 90 and delivery arm 86 as shown in dotted lines in FIG. 5. I employ a base check valve 122 in fitting 129 to slow down the feed stroke, at which time the arm 86 will snap back quickly. In retracted position, delivery arm 86 clears the stack of washers in feed tube 66 allowing the stack to move down and place the next bottom washer in position to be engaged by the delivery arm. During retraction of the delivery arm 86, the downward movement of driver piston 20 drives the nail through the aperture in the washer, removing the washer from the machine and applying it to the working surface under the head of the nail.

When trigger 55 is released causing driver piston 20 to retract upwardly, air pressure is supplied through passage 48 and pipe 95 to simultaneously drive piston 90 and delivery arm 86 for sliding another bottom washer to W.sub.1 position in pocket 70. Exhaust air from cylinder bore 91 is discharged through pipe 96 and port 41 in FIG. 11.

When nonmagnetic washers are to be used, i.e., plastic, aluminum, etc., I have adopted a substitute therefor, namely, air pressure. In FIGS. 12 and 13 I show a modified form of my invention wherein soleplate is provided with a vertical passageway 123 extending from and communicating with the interior of bore 91 between the bumper 92 and left-hand head of piston 90 as shown in FIG. 13. The passageway 123 communicates with passageways 124 and its branches 125, 126, and 127. Each of the terminal ends of branches 125, 126 and 127 are curved, as at 128, outwardly and upwardly therefrom terminating in an aperture 130 directed towards the washer W-1 as shown in FIG. 13.

Thus compressed air flowing through conduit 95 through fitting 129 into the bore 91 thru the passageways 123--127 inclusive and outwardly thru the apertures 130 will be directed to the bottom of the washer W.sub.1 retaining the washer in place subject to the nail and driver blade forcing it out of position to the work.

Thus all of the magnets required in the principle embodiment may be eliminated and ordinary blocks substituted therefore.

Claims

Having now described my invention and in what manner the same may be used, what I claim as new and desire to protect by Letters Patent is:

1. In a nailing machine having a reciprocating nail driver, a reservoir for holding a supply of washers on one side of the nail driver and in cooperative relation thereto, reciprocating means for feeding by a forward stroke thereof a washer from said supply to nailing position directly below the nail drive, means for holding said washer in said nailing position until said driver is operated, means for retracting said feed means in preparation for feeding another washer when said driver is operated, and control means having a first position for actuating the driving stroke of said nail driver and the retracting stroke of said feeding means and a second position for actuating the retracting stroke of said nail driver and the feeding stroke of said feeding means.

2. In a nailing machine having a reciprocating nail driver arranged to drive a nail, means to actuate said driver in a driving stroke, and means to retract said driver; means for holding a supply of washers on one side of said driver, reciprocating means for feeding a washer from said supply to nailing position directly below said driver, means to retract said feed means upon actuation of said driver and feeding a washer after actuation of said driver, means for holding a washer in said nailing position until said driver is actuated in a driving stroke, and control means having two positions, said driver-actuating means and said feed-means retracting means being responsive to one and said driver-retracting means and said feeding means to the other of said positions.

3. In a nailing machine having a nail driver arranged to drive a nail, a washer feed tube on one side of said driver, a soleplate having an opening positioned below and in axial alignment with said driver, a semicircular washer pocket above said opening on one side thereof, a reciprocating arm for sliding a washer from said feed tube into said pocket after operation of said driver, means for holding said washer in said pocket, first means for retracting said arm in preparation for feeding another washer and for operating said driver, and second means for retracting said driver and moving said arm in its forward feeding stroke.

4. In a nailing machine having a nail driver arranged to drive a nail, a washer feed tube on one side of a soleplate having an opening positioned below and in axial alignment with said driver, a washer pocket above said opening on one side thereof, a reciprocating washer feeder, first means for actuating said feeder in a feed stroke to slide a washer from said feed tube into nailing position in said pocket and for retracting said driver, and second means for actuating said feeder in a retract stroke and said driver in its operating stroke.

5. The device of claim 4 wherein means are provided to retain the washer in said pocket until rejected during a driver stroke.

6. In a pneumatic nailing machine having a driver, a driver cylinder, an air supply reservoir, an inlet valve between said reservoir and cylinder, a double acting piston for operating said inlet valve, and a trigger valve for connecting one side of said piston to pressure and exhaust for opening and closing said inlet valve; a washer feed tube on one side of said driver, a soleplate having an opening in nailing position for passing a washer through the soleplate when said driver is operated, a washer pocket above said opening on one side thereof, a washer feed piston in a double-acting cylinder, an air conduit connecting one end of said feed cylinder with said driver cylinder and reservoir when said inlet valve is opened by operation of said trigger valve whereby when said driver is operated, said feed piston is in a retract stroke and an air conduit connecting the opposite end of said feed cylinder with said reservoir when said trigger valve is released, to operate said feed piston in a feed stroke for sliding a washer from said feed tube into nailing position in said pocket.

7. In a pneumatic nail-driving machine having a driver and valve-controlled air supply and exhaust passages, means for holding a supply of washers, pneumatic means for feeding one washer at a time from said supply to nailing position beneath said driver after operation of said driver, fluid pressure connections between said feed means and said passages for operating said feed means, a soleplate having an opening in said nailing position for passing a washer through the soleplate with a nail when said driver is operated, and means independent of said feeding means for holding a washer in said nailing position above the bottom of said soleplate and over said opening until said driver is operated.

8. In a mailing machine having a nail driver arranged to drive a nail, means for holding a supply of washers on said one side of said driver, means for feeding one washer at a time from said supply to mailing position beneath said driver on said one side of the work piece, a soleplate on said machine having an opening positioned directly below and in axial alignment with said driver for passing a washer through the soleplate with a nail when said driver is operated, and means for holding a washer in said nailing position above the bottom of said soleplate and over said opening until said driver is operated.

9. A machine as defined in claim 8, wherein said holding means comprises magnets positioned above said opening engageable with the upper side of a washer adjacent the perimeter thereof in said nailing position.

10. A machine as defined in claim 8, wherein said holding means comprising a pair of constrictive spring arms arranged to clamp a washer by its opposite edges in said nailing position.

11. A machine as defined by claim 7 wherein said washer holding means comprises subjecting jets of air against the bottom of said washer.