US3275212A - Stapler - Google Patents

Description

Sept. 27, 1966 o. H. JoHNsoN STAPLER Filed July 22, 1964 INVENTOR.

OSCAR H. JOHNSON FIG.5

United States Patent O 3,275,212 STAPLER Oscar H. Johnson, Holden, Mass., assigner to Parker Mfg.

Company, Worcester, Mass., a corporation of Massachusetts Filed July 22, 1964, Ser. No. 384,336 7 Claims. (Cl. 227-132) This invention relates to a stapler and, more particularly, to apparatus arranged to drive wire staples for fastening and like purposes.

According to `common practice, stapling guns are provided with a ,spring-loaded hammer which -drives a wire staple. The hammer is retracted against spring pressure `by a hammer lifter which, at the upper end of the retraction stroke, engages a cam surface which serves to disengage the lifter from the hammer. In previously known Staplers, however, the act of tiring the gun causes the gun to change its position in the hand of the user in such a way that, by the end of the tiring stroke, the base of the stapling gun is no longer parallel to the surface into which the staple is to be driven. This results in a malfunctioning of the stapling driving operation and to improper fastening with the staple. Another diiculty experienced with the previously-known stapling guns is that the spring pressure at tiring is set in accordance with the Iheaviest staple to be driven. If a light-weight staple is to be used, the driving pressure is, nevertheless, the same amount and requires not only a considerable amount of extra work on the part of the user but, also, in the case of light staples, results in an improper driving force. When the force is too heavy, the staple may not be driven properly. Furthermore, the hammer actuating mechanism previously used is quite complicated and expensive and liable to be easily put out of order. These and other difculties experienced with the prior art devices have been obviated in a novel manner by the present invention.

It is, therefore, an outstanding object of the invention to provide a stapler in which it is possible to maintain the line of staple iiring at a iixed position during the operation of the gun.

Another object of this invention is the provision of a stapler in which Ithe loperating force for driving the staple may be changed by the user.

A further object ofthe present invention is the provision of a stapler having a simple operating mechanism which is inexpensive to manufacture and which is capable of a long life of useful service.

It is another object of the instant invention to provide a stapling gun -in which the geometric relationship between the fixed parts of the gun and the movable operating lever .are such that the gun Ican be kept in a iixed relationship to the surface to be stapled without tiring the operator.

It is a further object of the invention to provide a stapling gun in which the spring pressure for the staple driving operation may be changed to provide mo-re effective driving and to make the operation less tiresome to the user.

With these and other objects in view, as will be apparent to those skilled in the art, the invention resides in the combinaiton of parts set forth in the specification and covered by the claims appended hereto.

The invention, however, may be best understood by reference to one of its structural forms as illustrated by the accompanying drawings in which:

FIG. 1 is a perspective view of a stapler embodying the principles of the present invention,

F-IG. 2 is a vertical sectional view of the stapler,

FIG. 3 is a vertical sectional view of the stapler taken on the line III-III of FIG. 2,

"ice

FIG. 4 is `an inclined sectional View of a portion of the invention taken on the line IV-IV of FIG. 2,

FIG. 5 shows the same view as FIG. 3 but with the par-ts in a different relationship, and

FIG. 6 shows different operating positions of a rnodiiication of the invention.

Referring yiirst to FIG. 1, which best shows the general features of the invention, the stapler, indicated generally by the reference numeral i10, is shown as having a hollow housing 1=1 from one end of which extends at a right angle a base 12. At the other end, a grip 13 extends at a su-bstantal angle to the housing. Between the base and grip extends an actuating trigger` 14 which, in its position of repose, as shown in FIG. 1, extends parallel to the base 12. When the -trigger Iis at the other end of its stroke, however, it resides generally parallel -to the grip 13, as shown in dotted lines in FIG. 2.

Extending along lthe base |12 and hingedly attached to its `outer end is a carrier .15 adapted to be loaded with staples; the free end of -this carrier is held in place against the base by a latch 116. At the upper part of the housing -11 is located a slot 17 in which is carried a detent button l18.

Referring now to FIGS. 2 and 3, it can be .seen that a g hammer 19 slides vertically within the housing and is pressed to a downward position by a coil spring 21. At its other end, the spring presses upwardly against a cap 22 which consists of a block `of metal slidable in the housing and protruding from the top thereof. Underneath the hammer 19, the base 12 is provided with a block 23 of rubber, and the hammer itself is provided with an operating blade 24 in the usual way. Slidable in the base 12 is a follower 25 which is pressed toward the blade 24 by Ian elongated spring y2'6 contained in the carrier 15.

As is evident in FIG. 2, the grip 13 has the shape of a pistol grip and its general tcentreline extends at an obtuse angle to the general line of movement of the hammer r19. ln the preferred embodiment, it is made of a plastic and is configured to t the hand of the user very comfortably.

The cap 22 is provided with a horizontal bore 27 in which is carried the detent button 18. As Iis evident in FIGS. 3 `and 5, the cap 22 is vertically slidable between parallel spaced Walls 28 and 29 of the housing 11. The slot 17 appears in the wall t28, while a similar slot 31 is formed in the wall 29. Each of these slots 17 and 31 are similar .keyhole slots having a narrow portion above and a wide circular portion below, as is evident in dotted tlines in FIG. 2. The button 18 consists of a head 32, a shank y33 which exactly tits in the upper narrow parts of the slots 17 `and 311, .a head 34, and a reduced portion 35, which reduced portion is the same size as the shank 33. The two heads 32 and A34 are also the same diameter and ttit only the enlarged bottom portion of the slots 17 and 31. Extending into the ca-p 22 parallel to the bore 27 is a small bore 36 (see FIG. 2) in Vwhich resides a coil spring 37. A shallow circular recess 38 is provided as a counterbore to the bore 27 and is exactly the proper size t-o receive the head 34 in the manner shown in FIG. 3.

A lever 39 is pivotally mounted in the housing 11 on a pivot pin 41. At its other end adjacent the spring 21 it has pivotally mounted on it a lifter 42 which is connected t-o the lever by a pivot pin 43. The trigger 14 is pivotally mounted in the housing 11 by means of a pivot pin 44 and at a position spaced from the pivot pin 44 is provided with a roller 4S mounted on an axle 46.

As is evident in FIG. 4, the lever 39 is formed of two side anges 47 and 48 joined by a web 49. The flanges 47 and 48 are each provided with a notch 51 (see FIG. 2) directed toward .the lifter 42. Between the flanges 47 and 4S lies a bracket 52 stamped from sheet metal and having legs 53 and 54 extending laterally into the notches 51 in 3 the `flanges 47 and 4S. The bracket is provided with a finger 55 which is directed toward the lifter 42 which, in turn, is provided with a lug 56. Between the lug 56 of the lifter `42 and the linger 55 of the bracket 5-2 extends a coil spring 57. Also of interest is the fact that a thumb guard 58 is provided in connection with the trigger 14 to prevent .the user from getting his hand caught in the internal workings of the gun.` Also, the latch 16 is pivoted on ay pivot pin 59 and is maintained in locking position by a wire spring 61.

Referring to FIIG. 6, which shows a modification of the spring-pressure changing apparatus, it can be seen that a detent button 62 consists of two separated portions 63y and 64 pressed apart by a coil spring 65. The two portions are slidably carried in a bore 66 in the cap 67. As before, the housing is provided with two spaced parallel walls 68 and 69 having keyhole sl- ots 71 and 72, respectively. The portion 63' is provided with a reduced end which ts in the narrow upper portion of the slot 71 and a larger portion which tits in the large part of the slot 71, this last-named portion being not quite as large as the main body of the portion 66 of the detent button which rides in the bore 66. The portion 64 is similarly arranged in connection with its slot 72.

The operati-on of the invention will now be readily understood in view of the above description. With the carrier 1-5 held in place against the base 12 by the latch 16, the user grasps the grip 13 in the heel of his hand and wraps his ngers around the trigger 14. His forefinger would be pressed forwardly against the guard S8. The trigger 14 is then drawn slowly toward the grip 13. The trigger rotates about its pivot pin 44 carrying the roller 45 up against the web 49 of the lever 39. This eventually causes the lever to rotate counterclockwise (as viewed in FIG. 2) about the pivot pin 41 and lifts the other end of the lever upwardly. The lever, therefore, operates through the pivot pin 43 to carry the lifter 4-2 upwardly. The lifter engages a suitably shaped recess in the hammer 19` and, therefore, carries the hammer upwardly against the pressure of the coil spring 21. Eventually, the upper end of the lifter 42 engages a cam surface in the usual way, as shown in dotted lines in FIG. 2. This cam causes the upper end of the lever to be moved to the left, thus causing the lower end t-o be moved to the right and to leave the recess in the hammer 19. The hammer thus released travels downwardly striking against the rubber block 23. In the meanwhile, however, during the upward travel of the hammer 19, the follower 2S, under the action of the spring 26, pushes the staples against the inside surface of the housing 11, so that one staple occupies the position originally occupied by the blade 24. When the hammer moves downwardly, the blade, therefore, strikes the staple and drives it into the work.

Depending on the size of the staples and the type of work t-o be done, it is desirous that the position of the upper end of the spring 21 be changed so that the spring pressure at the start of the downward stroke of the hammer is exactly the right am-ount. -If a light stroke is desired, the cap 22 should be adjusted in the housing so that it extends upwardly o-f the housing. When a higher spring pressure is desired, the cap should be in a lower position. This lower position is shown in FIGS. 1 and 2 of the drawings; the position of the button detent 18 would be the one shown in FIG. of the drawings. In that position, the head 32 resides in the lower enlarged part of the slot l17, while the head 34 resides in the enlarged lower part of the slot 31. The cap 22 is in its lower position. The spring 36 operates on the inner surface of the head 34 and maintains the entire detent button 18 in its lefthand position so that it cannot move upwardly, even though the spring 21 presses against the bottom of the cap 22. In this condition, the spring 21 is under its greatest compression at the top of the stroke (just before t-he lifter 42 is removed from the hammer) and the greatest force results when the hammer strikes the staple.

l It also requires the greatest amount of work on the part of the user of the gun, and this position should not be used unless this extra force is necessary properly to drive the staple.

If it is desired to provide a smaller spring force, the operating mechanism is set in the condition shown in FlIG. 3. To accomplish this (the apparatus being in the condition shown in FIG. 5), the user presses against the reduced portion 35 of the detent button, so that it moves into the recess 38 in the cap 22, despite the pressure of the spring 36. Then, it is possible to move the shank 33 and the reduced po-rtion 35 up into the upper narrow portion of the slots 17 and 31. The cap 22 is then in its high position and the spring pressure would be less at the time of the release of the hammer 19. In order to return the apparatus to the condition shown in FIG. 5, where a high force is obtained from the spring, it is only necessary to hold the housing 11 in one hand and press downwardly on the cap 22. When the detent button 18 reaches the bott-om of the slots 17 and 31, the spring 36 will press it to the right and the heads 32 and 34 will move into the enlarged lower portions of the slots and lock them in place.

When a gun constructed in accordance with the present invention is operated, it can be seen that the operator keeps the heel of his hand against the upper part of the grip 13, so that the entire fixed portions of the gun, Le., the grip 13, the housing 11, and the base 12, remain fixed relative to the rest of his arm and body. It is possible, therefore, to keep the gun pointed in an exact accurate direction by using this method. The lingers serve to operate the trigger 14, but this does not change the position of the gun as was true of previously-known devices of this kind. It should be observed that the spring 57 which operates between the lifter 42 and the lever 39 maintains them at the greatest obtuse angle possible unless the trigger 14 dictates otherwise. Thus, the trigger in its normal position will be pressed downwardly into a position generally parallel to the base 12. The roller 45 in operating on the lever 39 simply rolls along the bottom of the web 49' which produces a very smooth action and a large mechanical advantage.

The operation of the detents in FIG. 6 are such that inward pressure on the portions 63 and 64 will permit them to be moved upwardly into the narrow portions of the slots 71 and 72, so that the cap 67 can occupy a highpower position. When it is desired to move to a lowpower position and move the cap 67 downwardly, it is only necessary to press the cap 67 downwardly so that the two portions 63 and 64 of the detent button 62 move outwardly and the next or enlarged portion of the parts move into the enlarged lower portion of the slots 71 and 72 and are locked in that position.

It can be seen, then, that by the operation of the present invention, it is possible to change the spring pressure at the moment of hammer release to either of two desired positions, i.e., a lightor a heavy-power position. The change from one to the other is easily accomplished by relatively simple mechanism. It is possible to drive staples not only in a comfortable position of the hand and arm but also without rotating the entire gun during the stapling operation because of the need to press a trigger with the heel of the hand, as in the previously-known practice. Furthermore, the operating mechanism is not only smoothly operating but, because of this smoothness, is capable of a long life of useful service. There are no intense force factors involved that tend to break and wear the mechanism.

It is obvious that minor changes may be made in the form and construction of the invention without departing from the material spirit thereof. It is not, however, desired to confine the invention to the exact form herein shown and described, but it is desired to include all such as properly come within the scope claimed.

The invention having been thus described, what is claimed as new and desired to secure by Letters Patent is:

1. A stapler, comprising (a) an elongated base adapted to carry a supply of staples and to feed them toward one end,

(b) an elongated housing extending at a right angle to the said base and having a hammer movable longitudinally of the housing toward the said one end to drive a staple,

(c) an elongated cantilevered grip extending at a sub stantial angle to the housing at the end opposite the end which is associated with the base,

(d) a trigger for actuating the hammer hingedly fastened to the said housing between and extending in the same general direction as the base and the grip,

(e) a spring in the housing pressing with one end against the said hammer,

() a cap mounted in the housing and engaging the other end of the spring,

(g) means connecting the housing and the cap to lock the cap in one of a plurality of accurately-spaced positions relative to the housing for the selection of spring pressure and hammer force,

(h) a lever mounted in the housing for pivotal movement about one end,

(i) a lifter pivotally mounted on the other end of the lever and having a hook at one end for engagement with the hammer, and

(j) a roller mounted on the actuating trigger and engaging the lever between the ends.

2. A stapler, comprising (a) a base adapted to carry a supply of staples and to feed them to a driving position,

(b) a housing connected to the base and having a hammer movable toward the said driving position on the base to drive a staple,

(c) a spring in the housing biasing the hammer toward the said driving position,

(d) an actuating handle hingedly mounted on the housing,

(e) a lever consisting of two spaced, parallel anges joined by a web mounted in the housing for pivotal movement about one end,

(f) a lifter pivotally mounted on the other end of the lever and having a hook at one end for engagement with the hammer,

(g) a roller mounted on the actuating handle and engaging the lever between the ends, and

(h) a spring extending between the lever and the lifter and acting along a line substantially spaced from the axis of pivotal connection between the lever and the lifter, the spring embracing at one end a peg extending from the lifter and at the other end embracing a nger on a bracket associated with the lever, each flange of the lever being provided with a notch directed toward the lifter, the bracket lying between the anges and having laterally extending legs which lie in the said notches. 3. A stapler, comprising (a) a base adapted to carry a supply of staples and to feed them to a driving position, (b) a housing connected to the base and having a hammer movable toward the said driving position on the l base to drive a staple,

(c) a spring in the housing pressing with one end against the said hammer (d) a cap mounted in the housing and engaging the other end of the spring, the cap being slidably mounted between opposite parallel walls of the housing, two identical apertures being formed in the said parallel walls, and

(e) means connecting the housing and the cap to lock the cap in one of a plurality of accurately-spaced positions relative to the housing for the selection of spring pressure and hammer force, the means cornprising a button detent mounted in the cap for engagement with the apertures.

4. A stapler as recited in claim 3, wherein the apertures are keyhole-shaped and have a narrow portion and a large portion and wherein the button detent has a large portion fitting closely within the large portion of the aperture and a narrow portion fitting closely within the narrow portion of the aperture.

5. A stapler as recited in claim 3, wherein the detent consists of two cylindrical elements arranged end-to-end in a bore extending through the cap between the two apertures and wherein a spring lies between the two elements to bias them outwardly into the apertures.

6. A stapler as recited in claim 4, wherein the detent has two spaced heads adapted to t in the large portions of the slots and Shanks adapted to fit in the narrow portions of the slots and wherein a spring biases the detent toward a position in which the heads reside in the said large portions.

7. A stapler as recited in claim 6, wherein a counterbore is provided in the cap coaxial of the said bore to receive one lof the heads of the detent on occasion and wherein `a small bore extends into the cap parallel to the bore and opens in the said counterbore to receive the last-named spring.

References Cited by the Examiner UNITED STATES PATENTS 1,919,373 7/1933 Krantz 227-132 2,361,483 10/1944 Lang 227-132 2,492,509 12/ 1949 Vandervieren 227-132 3,149,339 9/1964 Johnson 227-132 GRANVILLE Y. CUSTER, JR., Primary Examiner.

Claims (1)

1. A STAPLER, COMPRISING (A) AN ELONGATED BASE ADAPTED TO CARRY A SUPPLY OF STAPLES AND TO FEED THEM TOWARD ONE END, (B) AN ELONGATED HOUSING EXTENDING AT A RIGHT ANGLE TO THE SAID BASE AND HAVING A HAMMER MOVABLE LONGITUDINALLY OF THE HOUSING TOWARD THE SAID ONE END TO DRIVE A STAPLE, (C) AN ELONGATED CANTILEVERED GRIP EXTENDING AT A SUBSTANTIAL ANGLE TO THE HOUSING AT THE END OPPOSITE THE END WHICH IS ASSOCIATED WITH THE BASE, (D) A TRIGGER FOR ACTUATING THE HAMMER HINGEDLY FASTENED TO THE SAID HOUSING BETWEEN AND EXTENDING IN THE SAME GENERAL DIRECTION AS THE BASE AND THE GRIP, (E) A SPRING IN THE HOUSING PRESSING WITH ONE END AGAINST THE SAID HAMMER, (F) A CAP MOUNTED IN THE HOUSING AND ENGAGING THE OTHER END OF THE SPRING, (G) MEANS CONNECTING THE HOUSING AND THE CAP TO LOCK THE CAP IN ONE OF A PLURALITY OF ACCURATELY-SPACED POSITIONS RELATIVE TO THE HOUSING FOR THE SELECTION OF SPRING PRESSURE AND HAMMER FORCE, (H) A LEVER MOUNTED IN THE HOUSING FOR PIVOTAL MOVEMENT ABOUT ONE END, (J) A LIFTER PIVOTALLY MOUNTED ON THE OTHER END OF THE LEVER AND HAVING A HOOK AT ONE END FOR ENGAGEMENT WITH THE HAMMER, AND (J) A ROLLER MOUNTED ON THE ACTUATING TRIGGER AND ENGAGING THE LEVER BETWEEN THE ENDS.

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