US3176592A

US3176592A - Fastener driving apparatus

Info

Publication number: US3176592A
Application number: US265840A
Authority: US
Inventors: Oscar A Wandel
Original assignee: Duo Fast Corp
Current assignee: Duo Fast Corp
Priority date: 1963-03-18
Filing date: 1963-03-18
Publication date: 1965-04-06
Anticipated expiration: 1982-04-06

Description

. A. wANDEL FAS TENER DRIVING APPARATUS April 6, 1965 Filed March 18, 1963 \00 60 627%@ so es.

BY Mum, /falmmm @fm/m Arx/65% United States Patent O Y 3,176,592 FASTENER DRXVHQG APPARATUS Gscar A. Wandel, Mundelein, iii., assigner to Fastener Corporation, Franklin Park, lll., a corporation of Illinois Filed Mar. 13,1963, Ser. No. 255,840 Claims.V (Cl. 91-457) This invention relates to a fastener driving apparatus and, more particularly, to a fluid actuated device for driving fasteners into a workpiece.

The present invention is an improvement on pneumatically actuated fastener driving apparatus of the type disclosed in United States Patent No. 3,043,272. in pneumatically actuated fastener driving apparatus of this type, it is desirable to provide a pneumatically actuated piston return mechanism which eliminates many or all of the disadvantages of the previous types of apparatus having spring actuated piston return mechanisms.

Accordingly, it is an object of the present invention to provide a new and improved iiuid actuated fastener driving apparatus, Y

Another object of the present invention is to provide a new and improved means for supplying a pressurized iluid to a cylinder for driving a piston therein which carries a fastener driving blade.

Another object is to provide `a fastener driving tool including new and improved means for exhausting fluid from a cylinder after a driving stroke to permit the return of a piston in preparation for another driving stroke.

Still another object of the present invention is to provide an exhaust valve assembly for a cylinder in a pneumatic fastener driving tool in which the valve assembly is opened and closed by engagement. with amovable closure element for the cylinder.

A further object ofthe present invention is to provide a new and improved fastener driving apparatus of the type described above which is rapid and reliable in operation, easily manufactured and assembled, simple in construction, and easily. serviceable.

In accordance with these andY many other objects and advantages, an embodiment of the present invention comprises a housing forming a chamber which is continuously supplied with a pressurized uid, such as compressed air. Within the chamber, there is provided a cylinder having an open end exposed to the pressurized iluid in the chamber. A piston is slidably mounted in the cylinder and carries a fastener driving blade at its lower end for driving a fastener into a workpiece.

A iluid actuated main valve means is provided adjacent the open end of the cylinder and is movable into and out of engagement with the open end forcontrolling communication between the upper orV open end of the cylinder and the chamber. Exhaust valve means are provided on the housing adjacent the open end of the cylinder for controlling communication between the upper end of the cylinder and theV atmosphere. The exhaust valve is provided with an operator which is engaged by and moved with the main valve to control the operation of the exhaust valve.

Upon actuation of the device, the main valve is pneumatically lifted out of engagement with the end of the cylinder to admit compressed airfor driving the piston and blade downwardly to drive the fastener into the workpiece. The lifting of the main valve permits movement of the exhaust valve operator to close the exhaust valve so that compressed air entering the upper end of the cylinder will not escape to the atmosphere.

In order to return the piston and` driving blade to its upper position in preparation for another driving stroke, the main valve is closed -against the open end of the cylinder. During this movement, the main valve moves the lCe engaged exhaust valve operator to open the exhaust valve allowing the air in the upper end of the cylinder to escape to theV atmosphere; This permits the compressed air acting on the lower surfaces of the piston to return the piston and driver blade to their normal position.

Many other objects and advantages of the present invention will become apparent from the following detailed description when considered in conjunction with the drawings, in which:

FIG. 1 is a fragmentaryY sectional view of a pneumatically operated fastener driving apparatus embodying the present invention;

FIG. 2 ris a sectional view taken substantially along line 2 2 of FiG. 1; v

FIG. 3a is an enlarged fragmentary sectional'view of an exhaust valve means included in the apparatus of FIG. l shown in an open or normal position; and i FIG. 3b is a view similar to FIG. 3a illustrating the exhaust valve means in its closed position. i

Referring now more specifically to the drawings, therein is shown a pneumatically operated fastener driving apparatus, referred to generally as 10, which includes a housing 12 defining a chamber 14 continuously supplied with compressed air. Within the chamber 14, there is provided a cylinder 16 having an enlarged upper section 18 terminating in an open upper end Ztl anda smaller diameter lower section 22 mounted in the lower end of the housing 14. An O-ring 24 is provided to prevent the leakage of air from the chamber 14 through a bottom wall 26 of the housing 12 around the lower section 22 of the cylinder. The chamber 14 is in continual communication with the middle portion of the cylinder 16 by means of a ring of ports 28 positioned at the junction ofthe upper section 18 and the lower section 22 of the cylinder; Within the cylinder 16, there is provided a slidably mounted piston assembly 30 having a generally radially extending upper piston portion 32 which slides in the upper section 1S and a generally radially extending lower piston portion 341'- which slides in the section 22 of the cylinder 16. The

pistons

32 and 34 are integrally joined by a central portion 36 of considerably smaller crosssection than either of the pistons forming a central cavity 38 in the piston assembly 3i) which is in continual communication with the chamber 14 by means of the ports 2S in the wall of the cylinder 16.

The piston portion 32 is provided with an O-ring 42 to seal the cavity 38 from the upper end of the cylinder `16 above the piston portion 32, and the lower piston :portion 34 is provided with a similar O-ring 44 Vto seal the cavity from the lower end of the cylinder below the piston portion 32. The lower end of the piston assembly 3Q is provided with a resilient bumper stop 46 which strikes the lower wall 26 of the housing and absorbs the shock of the driving stroke.

lIn order to drive a fastener as the piston assembly 30 moves rapidly downwardly on its driving stroke, there is provided a fastener driver blade 48 Whichis secured to the lower portion of the piston Vassembly by means of a pin 50 and an annular retaining ring 52. The lower wall 26 of the housing is provided with apertures 54 to allow fthe driver blade 48 to pass therethrough and to allow air to pass freely from the atmosphere into the lower section 22 of the cylinder below the piston portion 34. f

In accordance with one of the features of the present invention, there is provided adjacentthe upper open end of the section 18 of the cylinder a Yiiuid actuated main valve assembly 56 which includes a flexible diaphragm 5S movable into andV out of engagement with the open end 2t) of the cylinder to control the communication between the chamber 14 and the upper end of the section 18 of the cylinder 16. The diaphragm 58 is sealingly secured between the upper end of the housing 12 and a `a recessed annular shoulder 70 formed in the cap piece 60 adjacent the upper end of the cavity 64. A locking and sealing O-ring 7-2 is provided to secure the disk 66 in place and prevent leakage of air into or out of the chamber 64 around the edges of the disk. The central aperture 68 of the disk is providedrwith an O-ring 74 to slidably `and sealingly engage `a depending stem 76 of a piston valve assembly 78. The lower `end of the stem '76 is threaded and provided with a shoulder 80 in order to accommodate the diaphragm 58 and a stiifener 82 adjacent the upper surface thereof and a stilener 84 adjacent the lower surface thereof. The diaphragm 58 and stitieners 82 and 84 are secured on the threaded portion of the stem 76 against the shoulder 80 by a nut 86, and a seal is provided between this diaphragm and the stem 76 by an Caring 88. Thus secured, the piston valve assembly 78 will move up and down with the diaphragm 58 of the main valve 56.

In order to accommodate the movement of the piston valve assembly 78, there is provided in the cap piece 60 another chamber-90 which is concentrically located above the chamber 64 and separated therefrom by the disk 66. The piston valve assembly 78 is provided with a radially extending flange or piston 92, `and theedge of this piston is provided with an O-ring 94 which sealingly engages the side walls of the chamber 90 as the assembly 78 moves up and down. The upper surface of the disk 66 is provided with an annular cavity 96 which is vented to the atmosphere by means of a drilled passage 98 in the cap piece 60. Thus, the lower surface of the piston 92 iS always subject to atmospheric pressure regardless of its position in the chamber 90. The upper surface of the piston 92 is provided wi-th an annular recess 100 which is continuously in communication with an annular recess 102 provided in the upper wall surface .of the chamber 90. l y

The recess 102 is placed in communication with the chamber 64 in the cap piece 60 by a drilled passage 164 which comunicates with the chamber 64 through a port- 106 in the side wall thereof. The passage 104 is also in communication with a passageway 108 which runs from the cap piece 68 through a hole in the diaphragm 58 and a land portion 110 formed in the housing 12 within the chamber14 to a trigger valve assembly 112. The trigger valve assembly -112 is supported within a cylindrical well 114 formed in the housing 12 and is secured therelin by a set screw 116. lA trigger 11S pivotally mounted on the housing 12 provides means for manually actuating the valve assembly 112.r The passageway 108 extends through the wall of the well 114- and is aligned with a side port 120 which communicates with acentral valve chamber 122 of the assembly.

The chamber 122 is provided with an upper annular valve seat `124 vand a lower annular valve seat 126. The upper seat 124 encircles a supply port 128 which communicates with the interiorvof the housing 12 to supply compressed air therefrom to the valve chamber 122., and the lower seat encircles an exhaust port 130 which communicates between the valve chamber 122 and the atmosphere. `Within the valve chamber there is `provided a movable valve member. 132 which alternately seats against the upper and lower seats 124 and 126 but which is normally biased to remain seated against the lower seat Vto allow compressed air from the interior of the housing 12 to flow through the supply port 128 into the valve chamber 122 and out through'the pasageway 108 to the chambers 64 and 90.

The valve member 132 is provided with a depending valve stem 134 which is normally biased downwardly by means of a spring 136 acting against a washer 138 secured to the stem. A lost motion mechanism 140 includes a contact button 142 engaging the trigger 118. vWhen the trigger is actuated, the valve member 132 moves upwardly and seats against the upper` seat y1=24 momentarily and then returns to seat on the lower seat 126 even though the trigger is held in the depressed condition. Thus, in order to initiate successive power strokes, the trigger 1118 must be released each time and then depressed.

An additional feature of the present invention is the provision of a new and improved exhaust valve assembly 142 which is carried on a land portion 144 formed in the housing wall adjacent the upper open end 20 of the cylinder 16. The assembly 142 includes a drilled valve chamber 146 with an open upper end communicating with the chamber 14 and a blind lower end. A passage '-148 which extends between Ythe exterior of the housing 12 and the interior of the upper section 18 of the cylinder 16 adjacent the open end 20 also passes through the chamber 146. A valve member 150 is slidably mounted within the chamber 146 and includes an operating stem 152 extending upwardly therefrom and terminating in a cap 154 of greater diameter than the chamber 146 to limit the downward movement thereof. A recessed shoulder 156 is provided at the open end of the chamber 146 to accommodate the cap 154 when it is in its downward position (FIG. 3a) so that it will not interfere with the closing of the diaphragm 58 against the open end 20 of the cylinder.Y The member 150 is provided with an annular groove 158 which is located thereon at a proper position to provide a free flow of air from the upper end of the cylinder 16 to the atmosphere when the exhaust valve assembly 142 is in its normal or open position of FIG. 3a and to prevent communication between the upper end of the `cylinder 16 and the atmosphere when the exhaust valve is in the operated position shown in FIG. 3b. A biasspring 160 is provided in the blind end of the chamber 146 to urge the valve member upwardly -so that the cap 154 engages the lowergsurface of the diaphragm 58. Thus, when the diaphragm moves downwardly as in FIG. 3a, the spring is compressed and the exhaust valve assembly 142 is opened to vent the upper end of the cylinder 16 to the atmosphere. When the diaphragm 58 moves upwardly to the position of FIG. 3b to open the cylinder 16, the exhaust valve assembly 142 closes to prevent communication between the upper end of the cylinder 16 and the atmosphere.

The operation of the fastener driving apparatus 10 is eiiicient, reliable, and automatic. When a compressed air source is connected to the housing 12, the interior thereof and the chamber 14 is pressurized, and compressed air ows into the central cavity 38 of the piston assembly 30 resulting in an upward movement thereof because of the .difference in the cross-sectional areas of the

piston portions

32 and 34. Compressed air also ows throughv the supply passage 128,the valve chamber 122,

the passage of the trigger valve assembly 112, and the passageway 108 into the chamber 64 through the port 106 and into the chamber 90 through the passage 104. This Vresults in a downward force on the piston valve assembly Yis firmly seated against the top or open upper end 20 of the cylinder. As the diaphragm 58 moves downwardly, it engages the cap 154 to move the valve member 150 downwardly against the action of the spring to the position shown in FIG. 3a. This opens the exhaust valve assembly 142 to vent the upper end of the cylinder 16 to the atmosphere to `allow the upwardly directed forces acting on the piston assembly 30 to move the assembly to its uppermost position.

It should be noted that the upper surface of the piston portion 32 of the assembly 30 is relieved to accommodate the lower part of the stem 76 and nut S6 on the piston valve assembly. Also since the passage 148 is positioned below the top end 20 of the cylinder, a small `amount of air will be trapped in the upper end of the cylinder as it moves to its uppermost position. This trapped air is useful in providing a cushioned stop to the upward travel of the piston assembly but is not of sufficient magnitude to unseat the diaphragm 58 from the open end 20 of the cylinder. In addition, the air within the chamber 90 below the piston 92 is forced out of the passage 98 as this piston moves downwardly to seat the diaphragm 58.

The operation just described is very rapid and the apparatus is now ready for operational use in driving a fastener. When the operator depresses the trigger 118, it causes the valve member 132 to be moved upwardly to seat against the upper vvalve seat 124 spaced from the lower valve seat 126. Thus, air pressure in the chambers 64 and 90 is vented to the atmosphere through the passages 104 and 108, the valve chamber 122, and the exhaust passage 130. When this happens, the air pressure in the chamber 14 acting on the exposed lower side of the diaphragm 58 lifts the diaphragm away from the open end of the cylinder 16. Since the chamber 14 completely surrounds the upper end of the cylinder 16 except for the lands 144 and 110 (FIG. 2), the air ow into the cylinder is rapid, and the piston assembly 30 is forced rapidly downward. As the diaphragm 58 moves away from the open end 20 of the cylinder to the position shown in FIG. 3b, the valve spring 160 urges the valve member 150 upwardly to the closed position preventing loss of the air entering the upper end of the cylinder 16 to the atmosphere through the passage 148.

As the piston assembly 30 moves rapidly downwardly on the driving stroke, the blade 48 engages and drives a fastener. The termination of the power stroke of the piston 30 is cushioned by the resilient bumper 46 striking the bottom wall 26.

Because of the lost motion mechanism 140 previously described, the valve member 132 is only momentarily seated against the upper seat 124 and then returns to become seated on the lower seat 126 independent of the release of the trigger 118. When this happens, compressed air from within the housing 12 again flows into the chambers 64 and 90 through the supply port 128, the Valve chamber 122, the port 120, the passageway 108, the port 106, and the passage 104. This compressed air acts against the upper surface of the piston valve 92 and the upper surface of the diaphragm 58 to force the diaphragm downwardly into engagement with the open end 20 of the cylinder 16. The total downwardly directed force on the diaphragm 58 is much greater than the upwardly directed force thereon exerted by the air in the chamber 14. Consequently, the main valve assembly 56 closes rapidly.

As this happens, the valve member 150 is again moved downwardly to open the exhaust valve assembly 142 (FIG. 3a) so that the upper port of the cylinder 16 is vented to the atmosphere. Since the effective lower area of the piston portion 32 is greater than the upper area of the piston portion 34, the compressed air admitted through the ports 28 provides an upwardly directed force on the assembly 36 for returning this assembly to its normal upper position. During this return stroke, the air entrapped in the upper end of the cylinder 16 is discharged through the exhaust valve assembly 142. As the piston portion 32 passes the passage 148 in the wall of the cylinder section 18, the remaining air above the piston portion 32 is trapped and serves as a cushion to stop the upward movement of the piston assembly 30. The apparatus 10 is now ready to drive another fastener.

Although the present invention has been described with reference to a single embodiment thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this invention.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

l. A fastener driving apparatus comprising a housing forming a chamber continuously supplied with a pressurized uid, cylinder means in said chamber having an open endexposed to the pressurized lluid in said chamber, iluid actuated main valve means movableV downwardly into and upwardly out of engagement-with theV open end of said cylinder means for controlling communication between the open end of the cylinder means and the chamber, vent passage means formed in the side walls of said chamber and said cylinder means below the open end thereof and communicating between the interior y of the upper end of said cylinder means and the atmos-V phere,`and an exhaust valve means mounted in said vent passage means for Opening and closing communication in said vent passage means between the upper end of the cylinder means and the atmosphere, said exhaust valve means including an operator stem biased to extend upwardly above said open end to close said exhaust valve means when said main valve means is open adapted to be engaged by and moved downwardly by the main valve means to operate open the exhaust valve means when said main valve means closes the open end of said cylinder means.

2. A fastener driving apparatus as described in claim l wherein said exhaust valve means includes a valve passage having an upper end in communication with said chamber, a piston valve member slidable in said valve passage to open and close said vent passage means and biasing means in said valve chamber `for normally upwardly biasing said piston valve member to a closed position.

3. A fastener driving apparatus comprising a housing forming a rst chamber continuously supplied with a pressurized uid, cylinder means in said first chamber having an open end exposed to the pressurized fluid in said first chamber, iluid actuated main valve means including a flexible diaphragm having a lower surface movable into and out of engagement with the open end of said cylinder means for controlling the communication between the cylinder means and said first chamber, second chamber means defined in said housing having a piston means slidably mounted therein, means connecting said piston means and said diaphragm for moving the two in unison, means for selectively supplying the pressurized Huid to said second chamber -above said piston means and the upper surface of the diaphragm to move said diaphragm into and out of engagement with the open end of said cylinder means, exhaust valve means mounted on said housing for controlling communication between the upper end of said cylinder means and the atmosphere and including operator means engageable by and movable with said main valve means to open said exhaust valve means when said main valve means engages the open end of said cylinder means, and means for biasing said exhaust valve means to close when the main valve means is away from the open end of said cylinder means.

4. A fastener driving apparatus comprising a housing defining a first chamber having an upper end and adapted Y to receive a compressed fluid, a cylinder in said rst chamber having an open upper end adjacent the upper end of said rst chamber, a piston movably mounted in said cylinder, a movable diaphragm secured to the upper end of said first chamber and movable toward and away from the upper end of said cylinder to close and open, respectively, communication between the upper end of said cylinder and said first chamber, a second chamber in said housing adjacent the upper end of said iirst Vchamber having its lower wall formed by said movable diaphragm, a third chamber in said housing Vadjacent said second chamber, piston means slidably mounted in said third chamber, means interconnecting said piston means and said diaphragm, first passage means in said housing venting the lower end of said third chamber to the atmosphere, second passage means in said housing interconnecting the upper end of said third chamber above said piston means to the second chamber, exhaust valve means in said housing adjacent the upper end of said cylinder for venting the cylinder to the atmosphere, said exhaust valve means including an operator actuated by said diaphragm to open said exhaust valve means when said diaphragm is closed against the` upper end of said cylinder and to close said exhaust valve Vmeanswhen said diaphragm is away from said cylinder, and control valve means for selectivelyA connecting the second and third chambers to the pressurized fluid and the atmosphere.

5. A fastener driving apparatus comprising a housing forming a irst chamber continuously supplied with a pressurizeduid, cylinder means in said rst chamber having an open end exposed to the pressurized iluid in said iirst chamber, iluid actuatedV main valve means in- 8 cluding a flexible diaphragm having a lower surface -movable into and out of engagement with the open end of the cylinder means for controlling the communication bet-Ween the cylinder means and said rst chamber, second chamber means delined in'said housing having a References Cited by the Examiner UNITED STATES PATENTS 3,043,272 7/62 'Wandel 91--420 3,081,742 3/63 Goldring 91-454 3,106,134 10/63 Osborne 91-454 3,106,136 10/63 Langas 91-461 FRED E. ENGELTHALER, Primary Examiner. SAMUEL LEVINE, Examiner.

Claims

1. A FASTENER DRIVING APPARATUS COMPRISING A HOUSING FORMING A CHAMBER CONTINUOUSLY SUPPLIED WITH A PRESSURIZED FLUID, CYLINDER MEANS IN SAID CHAMBER HAVING AN OPEN END EXPOSED TO THE PRESSURIZED FLUID IN SAID CHAMBER, FLUID ACTUATED MAIN VALVE MEANS MOVABLE DOWNWARDLY INTO AND UPWARDLY OUT OF ENGAGEMENT WITH THE OPEN END OF SAID CYLINDER MEANS FOR CONTROLLING COMMUNCIATION BETWEEN THE OPEN END OF THE CYLINDER MEANS AND THE CHAMBER, VENT PASSAGE MEANS FORMED IN THE SIDE WALLS OF SAID CHAMBER AND SAID CYLINDER MEANS BELOW THE OPEN END THEREOF AND COMMUNICATING BETWEEN THE INTERIOR OF THE UPPER END OF SAID CYLINDER MEANS AND THE ATMOSPHERE, AND AN EXHAUST VALVE MEANS MOUNTED IN SAID VENT PASSAGE MEANS FOR OPENING AND CLOSING COMMUNICATION IN SAID VENT PASSAGE MEANS BETWEEN THE UPPER END OF THE CYLINDER MEANS AND THE ATMOSPHERE, SAID EXHAUST VALVE MEANS INCLUDING AN OPERATOR STEM BIASED TO EXTEND UPWARDLY ABOVE SAID OPEN END TO CLOSE SAID EXHAUST VALVE MEANS WHEN SAID MAIN VALVE MEANS IS OPEN ADAPTED TO BE ENGAGED BY AND MOVED DOWNWARDLY BY THE MAIN VALVE MEANS TO OPERATE OPEN THE EXHAUST VALVE MEANS WHEN SAID MAIN VALVE MEANS CLOSES THE OPEN END OF SAID CYLINDER MEANS.