US3169452A - Pneumatically actuated fastener apparatus - Google Patents

Description

Feb. 16, 1965 L. .1. DUGIN 3,169,452

PNEUMATICALLY ACTUATED FASTENER APPARATUS Filed June l2, 1962 2 Sheets-Sheet 1 IIO 2 Sheets-Sheet 2 l l l I L I l IL PNEUMATICALLY ACTUATED FASTENER APPARATUS ma m n l 2 4 Mm Wu W. 2 .4. I 4 m l G v l| l H A@ mmm m Feb. 16, 1965 Filed June 12, 1962 ATTN.

United States Patent Olice 3,ld9,452 Patented Feb. 16, 1965Y 3,169,452 PNEUMATICALLY ACTUATED FASTENER APPARATUS Leo E. Dugin, Evergreen Park, El., assiwor to Webeor, Inc., Chicago, Ill., a corporation of Ilinois Fiied .lune 12, 1962, Ser. No. 262,007 4 Claims. (Cl. 91-39S) The invention relates in general to fastener driving apparatuses and more specifically to improvements for a pneumatically actuated fastener apparatus for driving fasteners into a work piece.

Several different pneumatically actuated fastener apparatuses are currently in use and in general comprise an air cylinder and piston combination for powering a fastener driver blade through a guide way and into a fastener containing magazine to drive a fastener into a work piece. Conventionally, an air valve controls the admission of air pressure to the cylinder and the exhaust therefrom as the piston and fastener driver blade are reciprocated in the cylinder.

The prior art fastener driving apparatuses have generally taken one of two basic constructions. One construction provides a piston and fastener driver blade pneumatically actuated only through the working stroke with a compression spring disposed at one end of the piston cylinder to return the piston and 'fastener driver blade to the start position upon exhaustion of the air pressure on the piston. The other basic construction, more commonly used today in view of the necessity of increased air pressure to overcome the force of lthe compression spring and the frequent failure of the compression springs, provides a control valve Iarrangement to selectively permit air pressure to both sides of the piston to actuate the piston and fastener driver through the working stroke and the return stroke.

Heretofore, the prior art apparatuses have generally provided -a large reservoir of air pressure adjacent the piston cylinder .and upon the piston attaining the retracted starting position, a valve arrangement is actuated to permit the air pressure within the reservoir to be suddenly released against the piston to drive the fastener driver blade through the working stroke. Various valve configurations in combination with pistons, valves and pressure reservoirs have been devised in -an endeavor to obtain maximum effective force on the piston from the released vair pressure. Conventionally, the Valve arrangement between the reservoir and the piston cylinder is forced open by the air pressure that is to enter the piston cylinder. Y

It has been determined that the quick acting wide open valve yarrangements of the prior art apparatuses d-isposed between the pressure reservoir and the piston cylinder develops an appreciable loss of power on the working stroke due to the movement of the light piston being accelerated by the first burst of air pressure into the cylinder l'ahead of the subsequent solid wall of air pressure. This premature movement of the piston, subsequently powered by the solid wall of pressure catching up with it, defeats attaining maximum eiliciency of the pressure lavailable.

It is therefore the primary object of this invention to provide an improved pneumatically actuated fastener driving apparatus which overcomes the shortcomings and disadvantages of the prior art devices and attains maximum applied stroke power from the available air pressure.

It is the specific object of this invention to provide an improved pneumatically actuated fastener driving apparatus in which initial movement of the power piston opens the power valve arrangement permitting air pressure within the cylinder to force the piston through the working stroke.

Another object of this invention is to provide an irnproved pneumatically lactuated fastener driving apparatu-s construction which eliminates the large air pressure reservoir within the housing adjacent the power pistonv cylinder which could explode and fragment the casting if damaged or weakened.

A further object of this invention is to provide an improved pneumatically actuated fastener driving apparatus in which air flow passages, clearance and valve structure is provided to economically utilize the available air pressure with the greatest eiiiciency.

A further object of this invention is to provide an improved pneumatically actuated fastener driving apparatus in which the power valve arrangement, emitting air pres-v sure to the piston, is not subjected to direct lift pressures from the air supply to affect valve actuation, but is forced` to the open position by a momentary reverse movementV of the power piston as it is forced to its poised position upon actuation of the apparatus. j

A still further object of this invention is to provide an improved power valve arrangement for pneumatically actuated rfastener driving apparatuses which also functions as a pneumatic bumper for the return stroke of the piston.

Another object of this invention is to provide an improved pneumatically actuated fastener driving apparatus in which the piston cylinder is provided with ,a liner flared at its top to provide -a seating surface for the power valve land a manifold arrangement around the bottom for ready passage of piston return -air from the reservoir.

A further object of this invention is to provide an improved pneumatically actuated fastener driving appara-` tus which is rugged in construction, economical to manufacture and simple in design permitting easy assembly and disassembly of the operating parts with a minimum VVof time, tools and effort. i

Other objects and advantages of the present inventionwill be read-ily apparent from the description thereof, taken in conjunction with the accompanying drawings, in which:

FIG. l is a cut-away partially sectioned side elevational view of the pneumatically .actuated fastener apparatus of this invention, illustrating the power piston in the retracted starting position;

FIG. 2 is an end elevation-al view of the fastener apparatus; i i

FIG. 3 is a fragmentary partially sectioned side elevational view illustrating the head portion of the apparatus with the power piston and Vvalve mechanism in the position assumed immediately upon actuation of the apparatus at the start of the working stroke; Y

FlG. 4 is a fragmentary partially sectioned side elevational view illustrating the Vhead portion lof the apparatus with the power piston `and valve mechanism in the position assumed Vat the end of the working stroke;

FIG. 5 is a fragmentary partially sectioned side elevational view illustrating the head portion of the apparatus with thepower piston `and valve mechanisms in the position assumed during the return stroke; and g FIG. 6 is a sectional view taken along the line 6 6 of FIG. 1. l

Referring now specifically to FIGS. l and 2, the fastener apparatus 10 of this invention consists primarily of a unitary L-shaped contoured cast .housing 12 providing a handle portion 14 and head portion le to which a niagazine portion 18 is detachably secured. The case housing 12 is preferably formed from a suitablerlightweight metal spaced from the head portion 16 and directly connected -to a pressure source (not shown) through a threaded connector aperture 22 formed in the end wall 24 of the handle.

Integral with the handle portion'adjacent the end wall 24 and depending from one side thereof is a support arm 26 detachably secured, as indicated by the numeral 28, to a bracket 29 on the magazine portion 18. The releasable interconnection between the support arm 26 and the magazine portion 18 may be by any suitable conventional means and has been illustrated in the drawings `as by a conventional threaded bolt member 30.

Still referring to FIG. 1, a manually actuated starting mechanism 32 is disposed in the forward portion of the handle 14 and consists primarily of a poppet valve assembly 34 and a trigger assembly 36.

The housing 12 of the handle portion 14 is formed to provide a cylinder 38 in which the poppet valve 4% is received. The upper portion of the cylinder 38 provides an enlarged threaded portion 42 in which an end cap 44 is threadably secured. A seal member 4S is disposed beneath the cap 44 to seal the poppet valve assembly 34 from the atmosphere. The lower portion of the cylinder 38 tapers, as at 46, to-a concentric smaller cylinder 4S in which the poppet valve stem 50 is slidably positioned.

The end cap 44 has a centrally formed tapered recess 52 in the bottom wall which terminates in a flow passage 54 formed -at right angles to the center line of the cylinder 38. When threaded into the enlarged threaded portion 42, the ilow passage 54 is aligned with a flow passage 56 which opens to the pressure reservoir 20 in the handle.

The poppet valve is preferably formed from an elastomer, such as neoprene, with a cylindrical configuration having a diameter substantially less than the diameter of the cylinder 38. The stern 56, connected to the poppet valve, extends downwardly through the cylinder 48 to the outside of the housing. Axial slots 58 are formed in spaced apart relationship on the outer surface of the stem 50 to provide `exhaust ow passages from the cylinder 38 to the atmosphere when the poppet valve is in the upward or actuated position. As readily seen in FIG. 1, the poppet valve seals against the lower tapered portion 46 of the cylinder when in the downward or de-actuated position and seals against the tapered recess 52 in the end cap 44 when in the up or actuated position.

To facilitateactuation of the poppet valve, the trigger assembly 36 provides a trigger 60 pivotally secured to the outer surface of the housing 12 by a pinr62 which places the trigger in juxtaposition with the extended end of the poppet valve stem 50. It is readily understood that as the apparatus is gripped by the hand, the fingers may be positioned about the trigger 60 and tightened to force the stem 50 upwards to actuate the apparatus.

The head portion 16 provides a hollow substantially cylindrical conguration having an upper chamber 64, middle chamber 66 and lower chamber 68 concentrically formed with decreasing diameters within the housing.

A power valve assembly, indicated generally by thev numeral 70, is disposed in the upper chamber 64 and provides a valve 72 having a flange 73 extending outwardly adjacent the bottom thereof to which a exible diaphragm 74 is securely bonded. An abutment 76, on the valve 72, extends below the ange 73 and diaphragm 74 and is suitably covered by a bonding process with the resilient exible material of the diaphragm. The -abutment 76 on the power valve extends into the middle chamber and engages the upper surface of a power piston as will be explained. The upper portion or stem 78 of the valve 72 has a groove 80 formed in the outer surface adjacent the upper end for receipt of -a sealing ring 82. An exhaust ow passage 84 is centrally formed through the entire length of the valve 70 and terminates at the upper end in a concaved recess 86, concentric with the flow passage 84, in which a flow check ball 88 seats in sealed relationship during a portion of the operation of the apparatus as will be explained.

The diaphragm 74, bonded to the ange 73, provides an upwardly arched portion 90 between the periphery 'of the flange `73 and the outer periphery of the diaphragm. A serrated flow control ring 92, as best seen in FIG. 6, seats on a shoulder 94 formed between the upper chamber 64 and the middle chamber 66 to engage the under surface of the diaphragm adjacent the periphery thereof. The upper surface of the diaphragm adjacent its periphery, is in surface contact with a contoured securing ring 95 which provides an inner curved surface, complementary to the arched portion 90 of the diaphragm. The upper portion of ring 95 has a ow groove 96 formed in its outer periphery. A plurality of apertures 98, at spaced intervals, are Vformed through the ring 95 interconnecting the groove 96 with the upper chamber 64 above the diaphragm power valve 72.

The uppermost portion of the upper chamber 64 provides internal threads 100 in which a closure cap 102 is threadably received. The cap 102 provides a planar shoulder 104 adjacent the periphery of the lower surface to engage the upper surface of the ring and a sealing ring 106 disposed therebetween. Thus, it is readily understood that as the end cap 102 is threaded into the upper chamber 64 and comes into surface-to-surface contact with the ring 95, the periphery of the diaphragm 74 will be compressed in secured, sealing relationship between the ring 94 and the serrated ow control ring 92.

A concentrically formed slide passage 10S is formed in the under surface of the end cap 102 in which the valve stem 7S is reciprocally guided in sealed relationship. The slide passage 108 terminates adjacent the upper surface of the end cap and is interconnected with the atmosphere by a plurality of outwardly extending radial ow passages 110 through the cap. A compression spring 112 is disposed about the walls of the slide passage 108 having one end bearing against the undersurface of the end cap yand the other end bearing against the upper surface of the diaphragm covered iiange 73.

A tlow passage 113 extends from the cylinder 38 of the poppet valve terminating in the groove 9S in the ring 95. As will be readily understood from the operational description to follow, the ow passage 113 interconnects the upper chamber 64 above the diaphragm with either the atmosphere or the pressure reservoir 20 depending upon the position of the poppet valve 40.

Still referring to FIG. 1, a cylinder liner 114 disposed in the middle chamber 66. The lower edge of the liner seats on a shoulder 116 formed between the middle charnber 66 and the lower chamber 63 and provides a plurality of openings 11S therethrough in the form of a flow manifold to permit air pressure to pass therethrough from the reservoir 20. The upper edge of the cylinder liner 114 is formed inwardly, as at 120, to provide an upper'planar seat 122 for the diaphragm power valve 72. A shoulder 124 is formed in the outer surface of the cylinder liner adjacent the upper edge in which the innermost edge of the serrated ow control ring 92 engages to secure the cylinder liner in position.

The reservoir 20 is open to a portion of the middle chamber 66 permitting :air to enter the cylinder liner 114 through the ow manifold at the bottom and upwards through the ow.

A power piston 1,26 provides an upper portion 128 slidably received in the cylinder liner 114 and a lower portion 130 slidably received in the lower chamber 68. The upper portion 12S provides a planar upper surface 131,`and a groove 132 is formed in the side wall for receipt of :a seal ring 134 to form a leakproof seal between the upper portion 12S and the cylinder liner 114 as the piston reciprocates. The upper portion 128 and the lower portion 13S ofthe piston 126 are rigidly interconnected by a stem 136 of substantially less diameter.

The lower chamber 63 having a smaller diameter than the middle chamber 66 and cylinder liner 114, slidably receives the lower portion 130 of the power piston 126.

A groove 138 is formed in the side wall of the lower portion 130 for receipt of a sealing ring 140 in sealing relationship with the wall of the lower chamber 68 as the piston reciprocates. An abutment 142 is concentrically formed on the under surface of the lower portion 130 of the piston and is provide with a centrally formed axial slot 144 for receipt of a driver blade 146. An aperture 14S is radially formed through the abutment 142 intersecting the slot 144 through which a securing element 156, such as a rivet or pin, anchors the blade 146 to the piston 126.

The driver blade 145 extends downwardly through the lower open portion of the chamber and is slidably received in the forward portion of the magazine 18 for singular engagement with a fastener element.

The lower chamber 68 adjacent the bottom thereof provides a shoulder 152 on which a resilient buffer member 154 is received. As best seen in FIG. 4, the inside diameter of the buffer 154 is slightly larger than the diameter of the abutment 142 and as the power piston appreaches the lowermost point of the downward or driving stroke, the under surface of the lower portion 130of the piston will engage the upper surface of the buffer and compress it against the sides of the abutment to arrest the piston movement and absorb the driving force.

Referring now to FEGS. 1, 2, 3, 4 and 5, to operate the apparatus, an air pressure source is connected to the handle 14 at the threaded port 22. As the air pressure enters the conduit 2t), the component parts will assume a steady state or starting position illustrated in FIG. 1. The air pressure passes through the ow passage 56 into the poppet valve cylinder 38 and forces the poppet valve 45 downwardly into sealing contact with the lowered tapered portion 46 of the cylinder 3S. The flow channel 113 conducts the air pressure through the apertures 98 into the upper chamber 64 above the diaphragm 74. The air pressure above the diaphragm in conjunction with the force of spring 112 seats the power valve into sealing relationship against the planar surface 122 of the cylinder liner 11.4. conduit 2% flows upwardly through the serrated llow control ring 92 beneath the arched portion 90 of the diaphragm 74 and within the cylinder liner 114 through the flow manifold apertures 11S at the bottom of the liner to act on the lower surface of the upper portion 123 and the upper surface of the lower portion 130 of the power piston 1215. Since the lower surface of the upper portion 12.53 is of greater area than the upper surface of the lower portion 131i of the power piston 126, the piston will be moved upwardly to the position shown in FIG. l into surface-to-surface contact with the abutment 76 on the lower end the power piston 72. ln like manner, the air pressure under the arched portion 9i) of the diaphragm is con- 'lined to a smaller area than equal air pressure on the top of the diaphragm, thus the power valve is forced into the downwardly closed position. t

Referring now to FIG. 3, as the trigger 6G is manually moved upward against the stem 50 of the poppet valve 4i?, the poppet valve is forced upwards into sealing contact with the tapered recess 52 of the end cap 44 shutting off the supply of air pressure.` Simultaneously, as the poppet valve moves upwardly, the air pressure in the upper chamber 64 above the diaphragm '74 exhausts to the atmosphere through the flow passage 113 into the cylinder 38 and out the am'al slots 53 in the valve stem Si).

As the pressure in the upper chamber 64 above the diaphragm reduces, the pressure on the lower surface of the upper portion 128 of the power piston drives the power piston upwardly against the abutment 76, on the lower end of the power valve 78, breaking the seal between the diaphragm and the planar surface 122 of the cylinder liner 114.

Referring now to FIG. 4, as the power valve is forced upwardly by the power piston, air pressure from the conduit which is spaced from the cylinder beneath the arched At the saine time, the air pressure from the L portion 99 of the diaphragm, will be permitted to ow into the cylinder liner on top of the upper portion 128 of the power piston, arrest the upward movement of the power piston and drive the power piston downwardly. instantaneously, as the seal between the power valve and the planar surface 122 is broken and the air pressure is permitted to enter the cylinder 114 against the power piston 126, the force of the air pressure is also on the total lower surface of the diaphragm 74 causing the power valve to be forced upwardly, riding in the slide 108, until.

the check ball 88 comes into surface contact with the undersurface of the end cap 102, forcing the ball 88 into sealing contact with the concaved recess 86 to prevent the escape of the air pressure through the ilow exhaust passage 84. Thus, the full force of the incoming air pressure will he directed on the planar surface 131 of the upper portion 128 of the power piston. As the power piston moves downwardly, the driver blade 146 engages a fastener element and forces it down through the magazine 13 into a work piece.

Referring now to FIG. 4, as the power piston 126 approaches the extremity of the downward or working stroke, the abutment 142, beneath the lower portion 130 of the power piston, will be received within the buffer member 154. As the under surface of the lower portion 13@ of the power piston engages the upper surface of the buffer 154, the resilient material of the butler will be compressed into total surface contact with the sides of the abutment 142 to arrest the downward motion of the power piston and absorb the force created.

Referring now to FIG. 5, after the fastener element has been driven into the work piece, the trigger 60 is manually released permitting the air pressure on top of the poppet valve 40 to force the poppet valve into sealing relationship with the lower tapered portion 46 of the cylinder 38. With the poppet valve in the down or de-activated position, the air pressure in the cylinder 38 ows through the passage 113 to the upper chamber 64 above the diaphragm 74 and forces the power valve 72 downwardly into the steady state sealed position against lthe planar surface 122 of the cylinder liner 114.

As the air pressure on top of the power piston reduces, the greater force on the lower surface of the upper portion 128 of the power piston will move the piston upwardly into contact with the abutment 76 on the bottom of the power valve 72 to the steady state or rest position illustrated in FIG. l.

The air pressure above the upper portion 12S of the power piston 126, as the piston moves upwardly, escapes up through the exhaust passage 84 inthe power valve, unseats the check ball 8S and flows to the atmosphere through the radial passages 110 in the end cap 192.

Thus, it is now readily understood that the initial movement of the power piston 126 is in an upwardly direction to open the power valve '72 and that the sudden burst of air pressure entering the cylinder liner to act on the power piston must first arrest the upward movement of the piston before driving it downwardly. Thus, full force of the air pressure is available to act on the power piston start its downward movement rather than have the power piston subjected to an advanced portion of the available air pressure giving the power piston a premature downward acceleration before the full force of the air pressure is available to act on the top of the piston to derive maximum driving force.

The head portion 16 of the apparatus provides a simple straight through construction for ease of assembly and assembly of the operating component parts. The end cap 102 is easily removed from the top of the head portion permitting removal of the upper contoured ring of the power valve 72 and the entire power piston and liner may be lifted directly out without any additional tools being required, making the replacement of worn or broken parts to be accomplished in a minimum of time.

While the apparatus of this invention has been described as a manually operated fastener driving apparatus, it is to be understood that the actuating mechanism may be easily adapted for operation by means of an electrical solenoid to position the poppet valve either in the upward actuating position or in the downward steady state resting position. Thus, it is now readily understood how the advantages and objects of this invention are attained. The unique arrangement of the power valve in conjunction with the power piston wherein the force of the air to drive the power piston is confronted with the upward movement of the power piston before it can act to drive the piston downwardly, assures maximum momentum and force of the power piston and driver blade is attained from the available air pressure.

While a particular embodiment of the present invention has been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made withoutdeparting from the invention in its broader aspects. Accordingly, the appended claims cover all such changes and modications as fall within the true spirit and scope of the invention.

What is claimed is:

1. A pneumatically actuated fastener apparatus comprising:

a housing,

a cylindrical sleeve liner secured within the housing deining a power piston cylinder and having an opening through the wall thereof at the bottom,

an upper inwardly formed radial liange providing a planar valve seat for engagement by the valve arrangement and a port area substantially less than the power piston area,

a piston reciprocably mounted in said liner between said opening and said flange,

a drive blade actuated by the piston,

a pressure reservoir in said housing in open communication with the interior of the sleeve below the piston through said opening,

a exible diaphragm controlled power valve arrangement for closing the liner but operably contacted by the power piston on its movement inreverse direction to open the liner to the full force of the pressure in the reservoir to drive the piston and drive blade in a forward fastener driving stroke,

means for pneumatically closing said valve arrangement to close the liner creating a pressure differential on the piston to return and maintain the piston and drive blade in the returned position a predetermined distance away from its return limit of travel, and

a control valve arrangement to selectively control the pressure on said power valve arrangement to effect reciprocal movement of the piston and drive blade to singularly drive a fastener into a work piece.

2. The invention as called for in claim 1 including:

bumper means resiliently interengaging said piston and valve arrangement in their resting retracted position within said cylinder.

3. The `invention as called for in claim 1 in which:

said housing includes a head portion having an opening aligned with said liner and provided with an end cap substantially spaced from the open end of said liner, and

means on said valve arrangement reciprocably received in said opening in guided relationship.

4. The invention as called for in claim 1 wherein the housing has an `upper chamber closed by the diaphragm of said diaphragm valve,

a manually actuated poppet valve alternatively interconnecting the upper chamber above the diaphragm valve with the reservoir and atmosphere,

a valve stem secured to said poppet valve having a conduit therethrough extending outwardly from the housing and carrying a check valve for said conduit, and

said valve closing off the pressure from the reservoir to the upper chamber above the diaphragm valve and exhausting the pressure above the diaphragm valve to the atmosphere to initiate said reverse movement of the power piston to open the valve immediately prior to its forward driving stroke.

References Cited in the tile of this patent UNITED STATES PATENTS 1,971,048 Parsons Aug. 21, 1934 2,685,277 Schroyer Aug. 3, 1954 2,854,953 Osborne Oct. 7, 1958 2,872,901 Goldring et al Feb. 10, 1959 2,944,522 Doyle July 12, 1960 3,010,430 Allen et al Nov. 2S, 1961 3,026,849 Powers et al Mar. 27, 1962 Y 3,028,847 Sterner Apr. 10, 1962 3,035,268 Goldring May 22, 1962 3,056,964 Beckman et al. Oct. 9, 1962 3,067,724 Jenny et al Dec. 11, 1962 3,087,162 Saurenman Apr. 30, 1963 3,087,466 Tobias Apr. 30, 1963 3,094,901 Wandel et al June 25, 1963 3,106,134 Osborne Oct. 8, 1963 3,106,136 Langas Oct. 8, 1963

Claims (1)

1. A PNEUMATICALLY ACTUATED FASTENER APPARATUS COMPRISING: A HOUSING, A CYLINDRICAL SLEEVE LINER SECURED WITHIN THE HOUSING DEFINING A POWER PISTON CYLINDER AND HAVING AN OPENING THROUGH THE WALL THEREOF AT THE BOTTOM, AN UPPER INWARDLY FORMED RADIAL FLANGE PROVIDING A PLANAR VALVE SEAT FOR ENGAGEMENT BY THE VALVE ARRANGEMENT AND A PORT AREA SUBSTANTIALLY LESS THAN THE POWER PISTON AREA, A PISTON RECIPROCABLY MOUNTED IN SAID LINER BETWEEN SAID OPENING AND SAID FLANGE, A DRIVE BLADE ACTUATED BY THE PISTON, A PRESSURE RESERVOIR IN SAID HOUSING IN OPEN COMMUNICATION WITH THE INTERIOR OF THE SLEEVE BELOW THE PISTON THROUGH SAID OPENING,

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