US2585939A - Staple driving means for portable pneumatic staplers - Google Patents

Description

STAPLE DRIVING MEANS FOR PORTABLE' PNEUMATIC STAPLERS Filed Aug. 23. 1950 /2 1J I'IGQI. 2

Patented Feb. 19, 1952 STAPLE DRIVING .MEANS FOR PORTABLE PNEUMATIC STAPLERS Albert G. Juilfs, Newtown, Ohio, assigner to Senco Products, Inc., Cincinnati, Ohio, a corporation of Ohio- Application August 23, 1950, serial No. 181,025

'12 claims. (C1. 1 49 My invention relates to a portable pneumatic stapler primarily designed for stapling upholstery to the interior of automobile bodies, and in particular this invention relatesto novel staple drive mechanism for suchy a stapler. In my cope-riding application entitled `Staple Magazine and Feed Means for Pneumatic Staplers, filed November 23, 1949, Serial No. .128 941, and issued as U. S. Letters'Patent No. 2,585,941 on February 19, 1952, I have disclosed a staple feed mechanism. Reference is also made to my copending applications as follows: Staple Drive Mechanism for Portable Pneumatic Staplers, filed of even date herewith and bearing Serial No. 181,023; Staple Feed Mechanism for Portable Pneumatic Staplers, filed of even date herewith, bearing Serial No. 181,024, and issued as U. S. .Letters Patent No. 2,685,942 on February 19, 1952; and Valve Control System `4for Portable Pneumatic Stapler, led of even date herewith, bearing Serial No. 181.026, and issued as4 U. S. Letters Patent No. 2,585,940 on February 19, 1952.

A principal object of the present invention is to provide a portable pneumatic stapler 4in which the staple driving means are so arranged that the stapler can be used to drive staples in corners and crevices generally diicult to reach.

A. further object of this invention is to provide staple driving means which can be easily and quickly disassembled in order to clear the .staple gun of Iiamrned or bent staples.

Another object of this invention is to provide staple driving means of such type that the nose through which the staples are discharged and the driver for driving the staples can be quickly and easily changed without having to make any change in the stroke of the piston to which the staple driver is fastened.

A further object of the present invention is to provide a portable pneumatic stapler which is rugged and which can be manufactured cheaply.

These and other objects and advantages of my invention will become apparent to those skilled in the art during the course of the following description and from reference to the accompanying drawings in which like numerals are used to designate like parts throughout the same, and in which,

Figure 1 is a plan view of a portable pneumatic stapler constructed according to my invention and with parts broken away and parts shown in section in order to show the internal mechanism of the stapler,

Figure 2 is a cross section of the stapler shown 2 A in Figure 1 taken on the section line 2--2 of Figure 1, Y

Figure 3. is a cross section of a portion of the forward end of the stapler taken on the section line 3--3 of Figure 2, and

Figure 4 is a plan view of a strap which forms the top wall of the staple driving guide for driveway..

. Briey,inlthe practice .of my invention, a portable pneumatic. stapler including a cylinder having la piston is 'actuated by compressed air. The piston activates a staple driver which picks up va staple fromv the feed kand drives it through the material and into the base to which the material is kto be attached. l

The Ypiston is Vactuated by the compressed air in its drive but returned to its home position by a helical spring.

,In thewall of 'the cylinder carrying the staple driving piston, I provide an exhaust or leak vent for permitting the air between the piston and the base of the cylinder to'exhaust when the piston isv driven. Y This vent is positioned between the pistonin its retracted position, that shown in Figure 2, and the other end or base of the cylinder so that it is sealed off as the piston passes the vent and a cushion of air is formed between the piston and the end of the gun to absorb the shock of the movement of the piston. When air of very high pressure is used, this vent should be relatively small, while when very low air pressure isv used, the Vent should be larger. In order to provide a gun `or staple driver which may operate on different air pressures, I provide a nipple which is removable from the vent so that when high pressure is used, a nipple having a slight aperture ymay be screwed into the gun, while in using low pressure a nipple having a, larger aperture may be screwed into the gun.

4v Reierringto the drawings, I provide a cylinder l-locatedin the stapler vhousing 2 and carrying the piston 3. One end of the cylinderl is enclosed yby the plug or cylinder head 4. K There is a staple driver 5 pinnedY to the piston 3 which projects beyond the opposite end t of the cyl-inn der onto a guiding track l. rlhe end t of the cylinderj'l is closed by the housing 2. excepting for the track 'l which is closed bythe driver 5. yThe piston 3 is urgedk to its retracted position by the helicalV spring B`which'is based in an aperture 9 in the housing 2. The spring 5i is kept in line by rod or pin lll'. also based in the 2 andv aperture 9; This Vrod lil may be .fined to a plug I Gay-just nicely fitting within the bore or aperture 9. l

Since the portion of the cylinder I between the piston 3 in its retracted position and the end of the gun is thus sealed, a vent II is provided in a side wall of the cylinder I and a corresponding vent is provided in the housing 2. These vents are located between the piston 3 in its retracted position and the head 6 to permit the exhaust of the air within the cylinder when the piston is actuated. The vent II is positioned slightly short of the end S so that as the piston 3 passes the vent I I, air is entrapped between the piston 3 and the forward end of the gun, thus forming a cushion. In order to permit the use of diierent air pressures in actuating vthe gun, I provide a nipple I2 having an aperture I3. This nipple is located in the housing vent which corresponds to the cylinder vent I I. nipples I2 are provided having different sized apertures I3 so that the'appropriate nipple may be used with the gun, dependingon the air vpressure used to operate the gun. Also thestriking power of a staple gun constructed accordingito my invention can be easily changed without having to change the air pressure all over the plant. This is a distinct feature of my invention and one not to be found in other staple guns known to me.

The handle portion I4 of the gun contains a pressure chamber I5, the lower end of which is attached to the compressed air line. The upper end terminates in a passageway I6 which communicates with a chamber I1. Within the chamber I'.' is a valve I8 seated against one end of a. sleeve I9 so as to seal off the interior of this sleeve from the passageway I 6 and chamber I1. The valve I8 is mounted on a rod 20 within-the interior or chamber portion 2| of vthe sleeve I9. There is a passageway 22 which communicates with the chamber 2| and the inlet port of the cylinder I.

Slidablv mounted within the sleeve 2| is a bushing 23 which has an internal bearingr 24 to accommodate the end of the rod carrying the valve I8. Within this bearing is a relatively weak coil spring 25 which urges the rod 2li away from the closed end of the bushing 23. The bushing 23 terminates in an abutment 26 which is urged from the handle I4 by a relatively strong helical spring 21. I also provide a trigger 28 pivoted in the stapler body or housing 2 fo assist in the pressing of the operating button 26. Located between the valve I8 and a plug 29, and about an extension 20a of the rod 20, there is positioned a spring 30.

From the above, it is apparent that as the trigger 28 is squeezed and the button 26 pressed against the pressure of the spring 21, first of all the relatively weak spring 25 is depressed, since the pressure in the chamber I1 (plus the pressure of spring 39) against the valve I 8 is normally greater than the tension of the spring 25. However, as the spring 25 is further depressed, its tension increases until it bears the pressure of the air in the chamber I1 and spring 30. This opens the valve I8 slightly and then the spring 25 snaps the valve I8 wide open. This is explained as follows. At the instant the valve member I8 is first cracked, air bleeds past the member I8 into the chamber 2|, through the passageway 22 and through a longitudinal groove 32, to be described, where it meets the resistance oiTered by the small groove 32 and the piston 3. Pressure then builds up in the chamber 2| (the exhaust port 1I being closed as will be` described) and this pressure helps to counterbalance the tair Diiierent l 4 pressure in chamber I1 and the tension in spring 30. When this condition exists the compression of spring 25 serves to force the valve member I8 toits full open position suddenly. Such condition comes into existence very soon after the valve is Viirst slightlyU cracked in the manner described. A'It should be'noted that the result will be the same regardless 'of how slowly the trigger 28 is pulled; all that matters is that the spring 25 is finally so compressed that the valve is first cracked slightly-the sudden and complete opening of the valve will then occur automatically if the other parts are arranged as described. By this arrangement the operation of my staple gun is made independent of the touch of the operator; even andsmooth driving power and operation are thus assured at all times.

The inlet passageway 22 terminates in a port 3| of substantial size. There is a small groove 32 cut in the inner wall of the cylinder I under the piston 3 in its retracted position which runs to the rear of the piston 3, so that as air is admitted to the rear of the piston 3 by the groove 32 there is a relatively short, slow travel of the piston 3 and then a hard, rapid travel when it passes the port 3|. To this end there is provided an annular recess 33 near the head 4 which communicates with the groove 32.

Also provided in the handle I4 of the staple gun is an exhaust passageway 10. This passageway communicates with the chamber 2| through an exhaust port 1I formed in the sleeve I9. Another port 12 is formed in the sleeve I9 and this latter port communicates with the passageway 22.

The operation of this valve arrangement is as follows. When the trigger 28 is pulled and the button 26 thereby depressed the valve I8 is moved away from the end of the sleeve I9 in the manner above described. Air then passes from the chamber I5, through the passageway I6, into the chamber I1, past the valve I3 into the chamber 2|, through the port 12, into the passageway 22, through the port 3| and groove 32, and piles up behind the piston 3 thereby moving it away from the head 4. When the piston 3 moves past the port 3| a large amount of air enters behind the piston and drives it hard and fast whereby the staple driver H picks up a staple 41 positioned in the slot 1 and drives it into the work. Such drive is cushioned bv the air cushion governed by vent nipple I2. During this time the exhaust port 1I is blocked by the bushing 23.

On release of the trigger 2R the spring 21 returns the button 26 to the position of Figure 2 and the spring 8 returns the piston 3 to its starting position. Air collected between the piston 3 and head 4 is exhausted out the port 3| (and groove 32), through the passageway 22. through the port v12 into chamber 2|, out port 1I (valve I8 now seating against the end of sleeve I9) and iinally through the exhaust passageway 10.

The large air chamber I5 permits the use of relatively small air lines thereby making the staple gun very easy to manipulate.

The staple driver 5 is pinned at one end to the piston 3 and the head or driving end rides in a groove or slot 1. The slot 1 is closed by means of a plate 34 which has beveled or cut away portions 35 (see Figure 4). The plate 34 when placed in position over the passageway 1 rests on shoulders 36a of the member 36 (this member forming the bottom of slot 1 and may be considered as a base plate on which the plate 34 rests) and is held in position by the heads 31 of the bolts 38 resting in the indentations 35 (see Figure 3).

assenso This permits theV easy' removal andV replacement of the plate 34 and the.v availability of the passageway21iand? the nose` andi feed'. mechanism in the eventastaple becomes jammed. particular feature of the novel drive.- mecha,- n-ism-'just describede-and of the:` slotforming portions 354i and li--isl that by thisconstructionthe nose of" the gun, andthe driver 5 operating there'- in, can be changedwithout' changing 'the stroke oil the piston.` Such! 'arrangements make my staple gunV quite adaptable'toa great many jobs that cant be handled by conventionalguns having a fixed staple drive condition. 'For example, by replacing the staple driver 5 with a lon-ger member, andi bysubstituting longerv membersy for thel slot-forming portions 34- and.' 36,. azstaplergun having a `s'taple eiccti'ngfv nose which; protrudesz a considerable extent past the staple feed `track maybe achieved. 'A- gunfh'avingsuch afslong, relatively thin nose can be usedto-do'. stapling'in deep crevices notaccessible tothe ordinary gun. The amount by'which the length ofthe driver 5. can beincreasedis determined', see Figure 2', by the distance between the iorward end of the, driver 5, when the piston '3 is in its retracted position, and theiA pointat` which.` the feed track brings staples intofposition.atthe'slot 1.

Itshouldalsofbe noted that I have so arranged the driver 5 a'ndpistonv 3'that the driver is located or'pin-nedf to-the piston above its axis. By sopositioning the driver 5 I have provided a staple lgun whichl can 'be' used in crevices and the like heretofore'not accessiblev to' staple guns lof thisgeeral type;

VVThe staple feed comprises a staple track 40 having upstanding leg' members 40a' uponwhich rides a staple follower 46.' On 'top' of the staple track I provide a cover @8 which: is longitudinally slidable` in aA second track'p'ositioned over the staple-'trackl andfwhich in turn has a slot 50 which receives a projectingbossl 5I on the staple i'ollower ;461; One vend'of the cover 431' projects beyond the trackV and terminates in a hook shaped nger'g'ripBS- In order to feed the staples l1Y uniformly, IY provide a spring 43, one'end of which isattached near one end of the staple tracks l!!! and the body of which rides over a sleeve l2A near the-other or staple feeding end of the track. The other'end of the spring 43 is attached to a pin 45v carriedby thev staple follower 4G; This spring lies' within the upst'anding legV members 40a of the track vlil and is straddled by the staples which are placed about the track. Byl this means the springwhich feeds-the staples is extremely long,

so that tension at all times is uniform. In loading the stapler, the' coverll' is pulled down along its track. This in turn pulls the staple follower 46 towards one end of its track. Staples are then placed about the track, the cover forced completely in-to its track, and the follower moved against the stack of staples by the spring 43; 'Ijhe slot 5I) in the cover 4Q permits the coverA to be forced Yinto closed position even thoughthe" follower must initially remainnear that end of its track removed from the gun nose, andj-it also permits the follower 46. tomove along the track and feed the staples as so urged by the spring 43. It is to be understood that other means of feeding staples into the slot 1 in front of the driver 5 may be used.

By the above construction, a staple feeder is provided which permits the easy loading of the whole staple track without the necessity of having to completely remove any single part.

The staples 41 are continually fed into the nose ofthe gun and. positioned; in the slots 1 between the'members 34Jand 36 by the spring 43 and follower 46:.: When the driver 5' has picked up one of the staples and forced it out of `-the gun, another'v staple will be forced into the slot as the driver returns to its retracted position' as seen in Figure 2.

In order to permit the easy manipulation of my gun, I provide a swivel coupling at the end of the chamber I5 and the handle I4 of the gun.

IThis vswivel connection consists of a nipple 51 screwed into the end of the chamber I5 and having a bore 58. A second nipple 59 is slidably p0- sitioned in the bore 58 of the nipple 51 with an annular head 6G within the chamber I5. The head 65 isf larger than the body portion 59, so a shoulder orf iiange is formed which projects out over the inner end of the nipple 51 and prevents the nipple 59 from sliding out. An air passageway 6I is drilled through the nipple 59 and its outward end 62 is screwed into a hose coupling 63.

Between the head 60 of the nipple 59 and the end of the nipple 51, I provide an annular gasket 64.

lirom the above, it is apparent that when pressure is built up in the chamber I5, appreciable torce is exerted against the head 65 of the nipple 59 attempting to drive it outwardly. However, this` pressure forces the head 6D against the gasket 5,4 and thus provides a tight seal between the nippleV 5,9 and the chamber I5. The nipple 59 may, however, be rotated within the nipple 51 and permit the easy movement of the gun during its operation.

liroml the above, it is apparent that I have provided a portable pneumatic stapler which is compact and light and which may be used in remote and inaccessible spots and corners;

' The stapler may beused on air lines having diiterentjairv pressuresI by merely changing the vent nipple I2 (Figure 1) to accommodate the dinerent pressures. A novel feed is provided for the staples which permits a maximum of staples torbe loaded without any projections riding with the-staples which would catch in the clothing of the operator and tend` to destroy the feed.

The connection between the air line and the gun itselfA is rotatable and hence the gun may be handledand pla-cedV in diierent positions with a minimum of diiiculty.

' The passageway Which accommodates the staple driver 5` and the port through which the staples' are; fed into the nose of the gun are easily accessible by the mere removal of the two or more f Apositive: trigger mechanism is provided which insures the complete and eicient stroke of the piston no matterV hnwr slowly the. trigger mechanismis.depressed.y

'i-Itzisztof b'e'understood that modifications and changes can be made in my invention-without departing fromthe scope and spiritV thereof, and

`wlsiile I. have shown my invention as embodied in structions other than those disclosed herein. Having thus described my invention, what I claim as new and what I desire to protect by United States Letters Patent is:

1. In a portable pneumatic stapler, staple drive mechanism comprising a cylinder and cylinder head, a piston in said cylinder, means to admit compressed air into said cylinder near said head and behind said piston, a staple driver secured to said piston, said driver comprising a flat plate pinned to said piston, nose structure for said stapler having aslot therethrough adapted to receive said staple driver, means to feed staples into said slot ahead of said driver when said piston is against said head, means to cushion the driving stroke of the piston comprising an outlet vent located towards that end of said cylinder which is opposite said cylinder head and which outlet Vent is closed before the end of the driving stroke, the stapler being substantially closed tc the passage of air moved by said piston after said outlet vent is closed, and means to return said piston to said cylinder head when the supply of compressed air is cut oif.

2. The stapler of claim 1 in which said outlet vent is closed by said piston, and in which said return means comprises a relatively long and weak spring.

3. The stapler of claim 1 in which said piston is provided with a slot thicker than said blade and substantially Wider than said blade, said blade being pinned to said piston within said last mentioned slot for lateral movement with respect thereto.

4. The stapler of claim 1 in which said nose structure comprises a base plate, said slot being located in said base plate, and a cover plate secured to said base plate over said slot.

5. The stapler of claim 4 in which said base plate and said cover plate are removably secured to said stapler.

6. In a portable pneumatic stapler, staple drive mechanism comprising a cylinder and cylinder head, a piston in said cylinder, means to admit compressed air into said cylinder near said head and behind said piston, a staple driver secured to said piston, said driver comprising a at plate pinned to said piston, nose structure for said stapler having a slot therethrough adapted to receive said staple driver, means to feed staples into said slot ahead of said driver when said piston is against said head, and means to return said piston to said cylinder head When the supply of compressed air is cut off, said nose structure comprising a base plate, said slot being located in said base plate, and a cover plate secured to said base plate over said slot, said plates being removably secured to said stapler.

7. The stapler of claim 6 in which said flat plate is pinned to said piston to one side of the axis thereof.

8. In a portable pneumatic stapler, staple drive mechanism comprising a cylinder and cylinder head, a piston in said cylinder, means to admit compressed air into said cylinder near said head Vand behind said piston, a staple driver secured to said piston, said driver comprising a flat plate pinned to said piston, nose structure for said stapler having a slot therethrough adapted to receive said staple driver, means to feed staples into said slot ahead of said driver when said piston is against said head, and means to return said piston to said cylinder head When the supply of compressed air is cut off, said piston having a slot thicker than said blade and substantially wider than said blade, said blade being pinned to said piston Within said last mentioned slot for lateral movement with respect thereto.

9. The stapler of claim 8 in which said last mentioned slot is offset with respect tc the axis of said piston.

10. The stapler of claim 1 in which said outlet vent is provided with a nipple having an orifice therethrough, said nipple being removable from said vent.

11. In a portable pneumatic stapler. staple drive mechanism-comprising a cylinder and cylinder head, a piston in said cylinder, means to admit compressed air into said cylinder near said head and behind said piston, a staple driver secured to said piston, nose structure for said stapler having a slot therethrough adapted to receive said staple driver, means to feed staples into said slot ahead of said driver when said piston is against said head, means to cushion the driving stroke of the piston comprising an outlet vent located towards that end of said cylinder which is opposite said cylinder head and which outlet vent is closed before the end of the driving stroke, the stapler being substantially closed to the passage of air moved by said piston after said outlet vent is closed, and means to return said piston to said cylinder head when the supply of compressed air is cut off.

12. In a portable pneumatic stapler, staple drive mechanism comprising a cylinder and cylinder head, a piston in said cylinder, means to admit compressed air into said cylinder near said head and behind said piston, a staple driver secured to said piston, nose structure for said stapler having a slot therethrough adapted to receive said staple driver, means to feed staples into said slot ahead of said driver when said piston is against said head, means to return said piston to said cylinder head when the supply of compressed air is cut 01T, said nose structure comprising a base plate, said slot being located in said base plate, a cover plate disposed on said base plate over said slot, and means for removably securing said plates tc said stapler.

ALBERT G. JUILFS.

REFERENCES CITED The following references are of record in the 'file of this patent:

UNITED STATES PATENTS Number Name Date 274,941 Heysinger Apr. 3, 1883 1,936,915 Polzer Nov. 28, 1933 1,939,632 Rand-all Dec. 12, 1933 2,219,739 Duncan Oct. 29, 1940 2,445,674 Kendall July 30, 1948 2,482,993 Walker Sept. 27, 1949

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