US2975424A - Fastener device - Google Patents

Description

March 21, 1961 J. J. QUSSANI 2,975,424

FASTENER DEVICE Filed May 16, 1958 2 Sheets-Sheet 1 T1|:-E.A-

INVENTOR Jimzes J Oussarzzl ATTORNEY March 21, 1961 J. J. OUSSANI FASTENER DEVICE 2 Sheets-Sheet 2 Filed May 16, 1958 INVENTOR.

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IMHTIMIHIH United States This invention relates to fastener driving machines and more particularly to electrically powerized stapling machines.

My invention, in its more particular form, constitutes improvements pertinent to electrical stapling machines of the character disclosed in my Patent No. 2,403,947, granted July 16, 1946, and my applications Serial No. 496,465, filed March 24, 1955, now Patent No. 2,877,461, issued March 17, 1959, and Serial No. 659,678, filed May 16, 1957.

. Still more particularly, this invention relates to a powerized stapling device having novel improved staple driving and clinching characteristics.

Powerized-staplers are employed in a wide range of situations, the same machine often being called upon, without adjustment, to fasten together a small number of pages, or a large number, as in signature binding, pamphlet binding. Likewise, the powerized stapler will be used one moment to fasten lightweight papers and the next to fasten heavy cardboard; compressible materials and dimensionally stable materials.

It will be readily recognized that in each case the appearance and efiiciency of the resultant stapled cnnection will vary, depending upon the characteristics of the material used, the number of sheets, pages or layers of such material fastened, and the force of the staple driving thrust. If, for example, a staple is driven with an inordinate amount of force for the number of pages, sheets or layers, or type of material used, a depression or dimple is likely to surround the point of application, and some bunching, particularly of the upper few layers of fastened material will result. The dimpling and bunching phenomenon aforesaid not only detracts from the appearance of the stapled article, but results in a connection which, in use, will cause the topmost few layers, pages or sheets to tear rapidly and become disengagedfrom the saddle portion of the staple.

To overcome the dimpling and tearing tendencies aforesaid, it has sometimes been found necessary to use cardboard or other relatively rigid material as the top layer when stapling a relatively compactable paper or when the article to be stapled consists of but a few sheets. In some extreme cases, powerized stapling devices have driven the staples with such force that the saddle of the staple has been thrust entirely throught the top layers, again causing the user to resort to cardboard or the like as a top layer.

Attempts have been made to surmount the problem of overfastening with powerized staplers by reducing the driving force applied. While such attempts have achieved improved performance on articles comprising a few sheets, unsatisfactory performance in connection with heavier stapling jobs has been encountered.

In order to overcome the aforesaid disadvantages, it is an object of my invention to provide a powerized fastener having a novel staple driver, assuring efiicient op eration of the said stapler even when used with a wide range of materials and thicknesses of articles to be fastened.

A further object of my invention is to provide a novel fastener as aforesaid, with control means to assure that staples will be driven with a thrust not exceeding or falling below the acceptable range.

To attain these objects and such further objects as may appear herein or be hereinafter pointed out, I make reference to the accompanying drawings, forming a part hereof, in which-- Figure l is a perspective view of a stapler in accordance with my invention;

Figure 2 is a magnified section taken on the line 2-2 of Figure 1;

Figure 2A is a detail view of the switch;

Figure 3 is a section taken on the line 3-3 of Figure 2;

Figure 4 is a fragmentary section taken on the line 4-4 of Figure 3.

Describing my invention in detail, I provide a housing H having parallel side walls 10, 10a, separated from the base 11 by an open throat portion 12. A clamp arm member 13 is vertically swingably mounted on the shaft 14 extending between the walls, 10, 10a of the housing H. The arm member 13 is normally maintained spaced from the base 11 by the upward biasing action of a tensioned coil spring 15 which is secured at its upper end to the stud 16, extending inwardly from the wall ltla, and at its lower end 17 to the bracket 18, secured in spaced relation to the arm 13 by upstanding ears 33a.

Upward swinging of the arm 13 under the influence of the spring 15 is limited by the contact of the stop 19 extending from the bracket 18, with the cushion 20 forming the under-surface of the solenoid 21.

The solenoid 21, which is supported within the U-shaped bracket 22, is secured to the housing H by means of bolts passing through bosses 23, 23 on the wall 10a, into complemental threaded apertures in the said bracket 22. A staple carrier or track 24 of the usual U-shaped cross section is secured coaxially to the arm 13, access for loading the said carrier with staples being provided by the hinged closure capping element and staple guide 25, normally maintained in the closed position shown by the interengagement of the lugs 26 with latch notches 27 of the spring loaded dogs 28, as more particularly described in my applications aforesaid.

Staples mounted on the track or magazine 24 are urged, under tension, to the forward or driving position adjacent the capping member 25 by the biasing pressure supplied by the sleeve guided spring 29 to a staple pusher 30a (Figure 3) which rides on the staple carrier track 24 and contacts, as more specifically described in said ap plications, the rearmost of a row of staples. The staple pusher is operatively connected to an off set retractor arm 30, which arm is adapted to be maintained in rearward position by engagement over the dogging lug 31, thereby temporarily to relieve the row of staples from the pressure of the spring 29 to facilitate loading.

A driver arm 32 is pivotally mounted on the pivot pin 33 trunnioned on the clamp arm 13 from upstanding ears 33a. The two arms are normally maintained in spaced relation by the interposition of a relatively stiff spring 34, supported on the pin 33 between said arms and ears 33a. A driver blade 35 is slidably guided between the capping closure element 25 and the end of the track or magazine 24, the upper end 36 of the said blade being secured adjacent to the end 37 of the driver arm 32 through the medium of a stud 38 which passes through an aperture 39 in the blade 35 and is secured between depending fingers 40 extending from the arm 32.. The aperture 39 and the spacing of the fingers are arranged to provide a slidable fit and clearance with relation to the stud 33, thereby to prevent buckling and consequent binding as the blade 35 slides within the guiding space between the capping element 25 and the track magazine end 24. Upward swinging of the driver arm 32 relative to the clamp arm 13 is controlledly limited by the provision of adjustable stop bolts 41 extending downwardly from the bracket 18 into contact with the arm 32.

Motive power is transmitted to the clamp and driver arms 32 from the solenoid 21 through the medium of a high inertia armature 42 slidably guided within the said solenoid 21.

The lower end 43 of the said armature is provided with a captive roller 44, arranged to contact and bear against a cushion or pad 45 atfixed to the driver arm 32. A relatively weak coil spring 46, interposed between the armature cap 47 (see Figure 2) and the bracket 22 normally maintains the armature 42 in an upward position.

The carrier arm 13 is provided further with an extended longitudinal rail 48 which is secured in laterally spaced relation to the said arm by bolts 49, 49 and spacers Stl, 59.

The housing H is provided on a side wall 10 with an extended depth edge gauge slot 51. An electrical control 52 is adjustably mounted, to be securable at any point along the said gauge slot 51, a threaded knurled knob 53, adapted to be threaded over a complemental threaded stud 54, outwardly extending through said slot 51 from said control switch assembly 52, being provided for that purpose.

As the said control switch assembly 52 has been exemplified and described in detail in my aforementioned Patent No. 2,403,947, discussion herein will be limited to the instant invention. It is to be understood that it is not intended to be limited to the specific switch control assembly.

The control 52 is provided with a trigger 55, positioned to straddle the throat portion 12 and extend into a channel 56 in the base 11 of my device, the said trigger being adapted, upon insertion into trigger abutting position of sheets of paper or like articles to be fastened, to close an electrical circuit, thereby energizing the solenoid 21. The control switch assembly 52 is further provided with an inwardly extending abutment finger 57, which finger, when depressed, is adapted to break the said circuit and prevent closing thereof until the fastened articles are withdrawn from contact with the said trigger. The finger 57 is of a length to lie beneath the rail 48 in every adjusted position of the control 52.

It will be understood that the control switch 52 carried along the gauge slot 51, which is the same as described in my aforesaid Patent No. 2,403,947, consists of a pair of blades or conducting strips 59, 60 (see Figure 2A), vertically supported in an insulating block 61 carried in a normally spaced-apart position at their terminals 62, 63, faced toward each other and carrying electrical contacts 64, 65. A pawl 66 carried by a depending arm 67 and terminating in a trigger 55 also carries the pawl 66 which normally, in the spaced-apart position of the blades, is latched on the leading one 59 of the pair of said blades 59, 60 described in said patent, so that when the trigger 55 is contacted by the work to be stapled, it also carries the leading blade 59 into contact with the trailing blade 60 and closes the circuit to energize the solenoid 21. The said pawl 66 has an extension 68 arranged to be positioned in the path of a slide 69 which carries the abutment finger 57 to lie in the path of the rail 48. Lost motion spacing between the slide 69 and the extension 68 from the rail 4-8 to the pawl 66 is allowed for the initial movement to overcome static inertia and dwell for clamping of the work. The blow of the rail 48 on the finger 57 on the extension 68 disengages the pawl 66 from the leading strip and breaks the circuit energizing the solenoid 21 and restores the contacts 64, 65 to their normal spaced-apart position.

Having thus described the components of my device, I

' ant ease 4 shall outline their timed inter-relation during the stapling operation.

With the device connected to a source of power and the electrical control 52 set to the desired edge-to-staple distance, articles to be fastened are inserted into the throat 12 until they contact the trigger 55, thereby activating the solenoid 21. Activation of the solenoid impels the armature 42 downwardly into contact with the driver arm 32, against the light biasing pressure of the spring 46. The impelling pressure of the armature on the driver arm 32 causes the clamp arm 13 to pivot downwardly about the shaft 14 against the biasing influence of the spring 15 between the studs '16 and the ears 33a, the angular relation of the clamp arm 13 and driver arms 32 remaining substantially the same by reason of the greater stiffness of the spring 34 than the coil spring 15 and the mechanical advantage of leverage.

As the clamp arm 13 nears the anvil portion 58, the rail 48 contacts the finger 57 extending from the electrical control 52, thereby deactivating the solenoid '21 by releasing the coupling of the pawl which initially drew the contacts together. The momentum before the driving action built up by the initial energized movements continues to force the clamp arm downwardly, until further motion of the clamp arm is prohibited by the limiting action of the articles to be fastened, the said articles being thereby compacted in the process of first activating the clamp arm.

Up to this point in the stapling cycle, the driver arm 32 has not significantly moved relative to the clamp arm, .due to the unequal spring forces and the mechanical leverage advantage previously mentioned. However, when further movement of the clamp arm is prevented by the articles to be fastened, the momentum remaining in the armature 42 even though the supply of current to the solenoid has been cut off causes the driver arm 32 and blade 35 to move through the remainder of the staple driving cycle against the pressure of the spring 34, and the resistive force of the paper as it is pierced.

I have determined that the above described powerized stapler may be used to fasten a great variety of materials of a wide range of thickness without displaying a tendency to dimple or bunch the fastened articles, and with out sacrificing the ability to perform heavy duty stapling operations, such as through many layered cardboard articles.

While it is believed that the improved operation of my stapling device may be explained as below, it is to be understood that my invention is not to be circumscribed by any such explanation herein advanced by me, as they are merely included as an aid in understanding my invention.

It is advanced by way of explanation that the improved stapling characteristics result from an automatic adjust ment of my device to the thickness and material to be fastened. The key to the automatic adjustability is the interplay of a constant-momentum driving assembly under the influence of a differential momentum reducing spring control.

At the point where the solenoid is deactivated, the clamp arm and driver assembly have achieved their maximum momentum, this momentum being a constant factor as it is in no way affected, up to the point of deactivation, by the nature of the material to be fastened. After deactivation, however, the springing arrangement of my stapling device progressively reduces the momentum of the stapling assembly so that fewer sheets of material to be fastened will be struck a less vigorous blow than will articles having greater thickness.

Thus, in effect, the thickness of the material itself directly proportionally varies the force with which a staple will be driven in the said material. The direct proportionate variation of my said device should be contrasted with powerized staplers heretofore known in which deactivation of the impelling means is somehow coordimated with actual driving of the staple, the result of such arrangement being that articles of only a few sheets or of high compressibility are actually subjected to an equal or greater stapling force than are thicker articles.

My stapling device likewise automatically softens the force with which staples are driven in compressible materials, since the inertia of the staple driver blade is reduced when the materials are compacted by the clamp arm.

The above described stapling device has great utility in being adapted, without damage to the articles to be fastened, to fasten many or a few sheets of widely varying compressibility characteristics.

Having thus described my invention and illustrated its use, what I claim as new and desire to secure by Letters Patent, is:

1. A powerized stapler comprising a base having pivotally mounted thereon a work clamp member adapted to compress a stack of sheets to be fastened, a staple driver overlying said work clamp and movable relative to said clamp member, electrical impelling means arranged to actuate said clamp member having activating and deactivating means on said base and high inertia means operatively associated with said driver, said last named means effective, upon compression of said stack, to operate said driver, said clamp member including mounted thereon other means effective prior to full compression of said articles to activate said deactivating means.

2. A powerized fastener assembly arranged cyclically to compress and then staple sheeted articles and the like comprising a base having an anvil portion, a work clamp member extending from said base movable toward and away from said anvil portion and arranged to compress articles to be fastened thereagainst, a staple driver overlying said clamp arm movable relative to said clamp member, electrical impeller means arranged to actuate said clamp member, and switch means on said base arranged to activate said impeller means upon insertion of the sheeted articles to be fastened, said means extending in the path of means carried by the clamp member to deactivate said impeller means upon depression of the clamp member prior to full compression and stapling of said sheeted articles.

3. A fastener assembly in accordance with claim 2 and including high inertia means arranged to operate said staple driver after deactivation of said impeller means.

4. A fastener assembly in accordance with claim 3 wherein said impeller means comprises a solenoid and said high inertia means comprises an armature therefor.

5. A powerized fastener assembly arranged cyclically to compress and then staple sheeted articles to be fastened comprising a base having an anvil portion, a work clamp member extending from said base movable toward and away from said anvil portion and arranged to compress articles to be fastened thereagainst, a staple driver pivotally mounted on said clamp member, said driver including high inertia armature means, solenoid means on said base arranged, upon activation, to magnetically influence said armature means and switch means on said base arranged to activate said solenoid means, upon insertion of sheeted articles to be fastened, said switch means including switch release means extending in the path of means carried by the clamp member to deactivate said solenoid means upon depression of the clamp member prior to full compression and stapling of said sheeted articles.

6. A powerized fastener assembly arranged cyclically to compress and staple sheeted articles to be fastened comprising a base, an anvil portion supported on said base adjacent one end of the base, a work clamp member comprising a fastener carrier having pivotal mounting means adjacent the other end of the base and movable toward and away from said anvil portion remote from said pivotal mounting under biasing influence adjacent said pivotal mounting, a fastener driver carried on a driver arm pivotally supported on said work clamp member and independently spring biased in pivotal relation to said work clamp member adjacent one end of said driver arm and guiding a fastener blade adjacent the other end toward and away from said work clamp member, means to actuate said driver arm supported by said base overlying said driver arm adjacent the latter end thereof, comprising a high inertia armature means and solenoid means assembly arranged, upon activation electrically, magnetically to influence said armature means, a switch assembly slidably carried over said base along said clamping arm having switch contacts and contact holding means, trigger means carried by said switch assembly for bringing said contacts into solenoid activating position and release abutment means for said contacts to deactivate said solenoid, the combination having an abutment actuating rail carried by said clamp arm along the path of said switch assembly, whereby to depress said release abutment means prior to full compression of the work to be stapled and prior to clinching of the staples to impel the driver into clinching position under the biasing influence of said driver arm.

References Cited in the tile of this patent UNITED STATES PATENTS 2,403,947 Oussani July 16, 1946

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