CA1189489A - Mandrel rivet-setting tool - Google Patents

Abstract

TITLE OF THE INVENTION
Mandrel Rivet-Setting Tool ABSTRACT
A mandrel rivet-setting tool which may be used for rivets having mandrels formed over a wide range of diameters and of a range of materials. The tool is biased to an open position by a spring which ensures that nothing gets stuck within the tool and which assists in cleaning the jaws of the tool by snapping the tool open to provide vibrations that will jar particles loose from the jaws.

Description

INTRODUCTION
This invention relates to a tool for se~ting mandrel rivets and more particularly to a hand tool which i5 manually operated. This invention is an improvement upon the tool shown in my earlier U.S. Patent No. 3,646,800 dated March 7, 1972 entitled ~Mandrel Rivet-Settlng Tool~
~ andrel rivets are widely used for securing together two or more wor kpieces in situations where there is access to only one side of the workpieces. These mandrel rivets are constructed to have an elonyated mandrel affixed to a head in a manner to permit the mandrel to be snapped off with the application of a predetermined pulling f~rceO A short, flanged tubular shank is positioned around the mandrel at the head end~ ~hen the shank is inserted into aligned holes in the workpieces to be joined and the mandrel is pulled away from the head, the head spreads out the shank to lock the workpieces bet~een the resulting flattened deformed end of the shank and its flange, and then to snap off the mandrel from the headO The mandrel is then removed from the tool and discarded.
Sever~l types of tools have been developed for inserting and actuating these mandrel rivets. (See, for example, U.S.
Patent Nos. 3,280,615; 3,324,700, 3,328,985, and, 3,399,5Sl). me purpose of the invention shown in my prior patent No. 3,646,800 is to provide an improved tool which can grip and hold a mandrel prior to inserting the rivet shank into th~ workpieces, which can be constructed to provide automatic ejection of the mandrel into a collector, and in which the grip can be adjusted for different mandrel metals.
me object of the present invention is to provide a further improved tool which is easier to operate, prevents .. . .. .

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pieces of the mandrel from becoming stuck in ~he body of the tool, and is essentially self cleaning.
To accomplish these objects, this invention is incorporated into the tool shown in my earlier patent, supra. A spring is incorporated into the tool between the handles, which biases them apart by overcoming the bias of the spring incorporated into the tool body. Conseq~ently, the jaws of the tool which are used to grip and pull the mandrel are biased to the open position~ to prevent mandrel parts from becoming stuck between them. Furthermore, when the handles are released, the spring between them forces them apart rapidly, and the vibration of the ~ool under this action shakes loose any small particles between the jaws.
The open biased position also makes the tool easier fcr the operator to use with one hand.
This invention accordingly comprises the features of construction, combination of elements and arrangement of parts which will be exemplified in the constructions hereinafter described and the scope of the inven~ion will be indicated in the claims.
- For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawings in which:

BRIEF FIGURE D SCRIPTION
FIG. 1 is a side view of the tool of this invention shown in its biased or open position;
FIGo 2 is an end view of the tool;
FIG. 3 is a cross section of ~he rivet-holding end of the frame;

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FIG~ 4 is a cross section of that portion of the tool where the frame and act~ating handle are joined for pivotal movement taken along line 4-4 of FIG. l;
FIG~ 5 is an enlarged, detailed cross section of one embodimerlt of the rivet holding and actuating mechanism showing the tool in the biased position and with the mandrel of the rivet in place in the body;
FIG. 6 shows the mechanism oP FIG. 5 in its mandrel-gripping and pulling position;
FIGS. 7 and 8 are perspective and cross-sectional views of one of the jaws used in gripping;
FIG. 9 is a top planar view of a pair of the jaws;
FIG. 10 is a fragmentary cross section of another embodiment of the rivet-holding and actuating mechanism using a threaded ring to adjust the compression of the spring;
FI~. 11 is a top planar view of the ring in FIG. 10;
FIG. 12 illustrates the incorporation of a mandrel collector in the embodiment of FIG. 10; and FIG. 13 is a fragmentary cross section of another embodiment of the rivet-holding and actuating mechanism having means for adjusting the compression of the spring and mandrel collecting means.

DETAILED DESCRIPTION
The hand tool of this invention is shown in side and end views in FIGS. 1 and 2. With the exception of the main spring between the handles and the facility for securing the ... .

spring in place, the tool i5 the same as in my earlier patent No. 3,646,800. The tool will be seen to be formed of a frame 10, an actuating handle 11 and a rivet-gripping and pulling echanism 12. The frame 10 and actuating handle 11 are joined for pivotal motion with respect ~o each other, and the rivet-gripping and pulling mechanism 12 is joined to the actuating handle 11 ~or axial motion within the frame 10.
The frame 10 comprises a forward head section 15, a fulcrum extension member 16 having an opening 17 for a bushîng and a flat stop member 18, and an elongated curved finger-engaging handle 19 which may be partially covered with a sheath 20 having a good gripping surface. The actuating, palm-engaging handle 11 comprises a forward section 25 which is bifulrcated into two arms 26 and 27 between which the fulcrum extension member 16 is positioned. Actuating handle 11 has a curved gripping end 30 which begins with an enlarged section 31 and is covered by a sheath 32 having a good gripping surface. The combination of the curved handles, the upper of which has the enlarged section 31, results in a comfortable ~rip for the user while maintaining his hand in the proper position. Threaded bores are provided along the top of the actuating handle for carrying anvils such as 34, 35 and 36 of various bore diameters.
The pivotal connection between the finger-engaging handle 10 and the actuating handle 11 is made through a pivot pin 4 0 (see FIG. 4) which is positioned within a bushing 41, located in opening 17, and in two flanged bushings 42 and 43 located in appropriately sized openings in arms 26 and 27. The pin is locked with s~itable ~nap rings 44 to prevent its axial 30 movement~

The handles 11 and 19 are biased apart by a main spring S
which lies between the handles and is supported in place as shown in FI~. 1. This arrangement is described in greater de~ail below.
A chamber 51 is defined within the head sec~ion of the frame (FIG. 3). ~mis chamber is of a configuration which permits axial movement of the cylindrical mandrel-gripping and pulling mechanism 12. The chamber 51 is open at the top and has a threaded opening 52 at what may be termed the muz~le end of the head 15. miS threaded opening is adapted to receive a threaded anvil 33, as will be subsequently explained. The lower portion of the chamber has a frustoconical conf iguration 53 defined by a slanting wall 54.
FIG. 5 is a detailed cross section of the mandrel-gripping and pulling mechanism in position to receive the mandrel, i.e., with the actuating arm 11 in its biased position pivoted to achieve maximum spacing from the finger-engaging handle which means that the mandrel-gripping and pulling mechanism 12 is in its lowermost positiun. In this condition, the mandrel of the rivet may be readily inserted. Then by squeezing the handles 11 and 19 together through a small arc in overcoming the bias of spring S the mandrel is held firmly in the tool, permitting the tool to be used as the means for introducing the rivet head and shank into the holes of the workpieces. This ability of the tool to hold the mandrel means that the rivets may be easily used for joining workpieces which would normally be in an awkward location if the rivet had to be hand-held in place until the tool was brought into position.
In FIG. 5 in which like tool components are identified by like reference numerals used in FIGS. 1-4, the rivet is seen positioned with respect to two workpieces 58 and 59 which are to be joined~ The rivet is comprised of a mandrel 60 which terminates in a head 61 which is joined to i~ in a manner to require a predetermined amount of force to break them apart.
A tubular shank 62 having a flange 63 is slipped over the mandrel and at~ached to the head. As the mandrel is pulled, it causes the head to deform and flatten out the shank, thus locking the workpieces 58 and 5g together be~ween the flange and deformed and flattened side of the shankO
The mandrel-gripping and pulling mechanism is contained within a sleeve 65 which defines an actuator bore 66. The sleeve 659 at its upp2r end is pivotally mounted to arms 26 and 27 by means of pivot pins 67 and 68 whirh are partially threaded for screwing into the arms and being locked ~hereto. In the embodiment of FIGS. 5 and 6, these pivot pins extend through the sleeve wall and into the a~tuator bore to serve as spring retaining means as described belowO
The sleeve has a generally frustoconical configuration at its lower end. me outer surface 70 ~FIG. 6) of this lower part of the sleeve essentially corresponds to the frustoconical con~iguration o~ slanting wall 54 of the inner wall of chamber 51. The lower inner wall 72 of the sleeve is also of a frustoconical configuration, the angle which it forms with the central axis of the sleeve being smaller than that formed by the outer surface 70. Since the sleeve must ride up and down on the conical surface 73 of the anvil 33 the lower edge 74 of the sleeve is cut a~ an angle to provide a surface which makes contact with anvil surface 73.
The anvil 33 is threaded for engagement with the threads of opening 52, and it has a bore 75 sized to permit the mandrel 60 of the rivet to be passed through it. The anvils 3~B9 34, 35 and 36 have bores of varying diame~ers ~o accommodate different sized mandrels. They are, of course, readily interchangeableO
The mandrel is gripped between two essentially semicircular jaw pieces 78 which are detailed in FIC~ 7, 8 and 9. ~hen assembled .in the sleeve as in FIGS. S and 6, the jaw pieces form an essentially frustoconical configuration corresp~nding essentially to that def ined by ~he inner wall 72 of the lower section of the sleeve and def ine between them a threaded or serrated mandrel-gripping channel 80. Each, essentially semicircular jaw piece i5 CUt to have a major upper planar surface 81 which slants downwardly toward the cen~ral axis of ~he channel. It is preferred that this major upper planar surface 81 be intersected by a minor planar surface 82 which approaches 90~ with the plane of the cen~ral axis. The presence of the minor planar surface 82 eases the opening of the jaws when a force is applied to the planar surface 81. In a similar manner the lower jaw pieces are cut to have a major lower planar surface 83 which slants upwardly ~0 toward the central axis of the channel and which is intersected by a minor planar surface 84 which may slant in the same manner but at a lesser angle which approaches 90 with the plane of the central axis. me angle at which the major planar surface is cut is chosen so as to achieve contact between ~he planar surface 83 and the conical surface 77 of the anvil against which it ridesO The minor planar surfac~ 84 serves the same general purpose as the minor planar surface 82.
A jaw actua~or member 88 in actuator bore 51 is positioned to apply force through contact of its inclined lower surface 8~ with the major planar surfaces 81 of the jaws. This actuator member has a bore 90 running throughout i~s length, this bore being of a diameter such as to permit passage of the largest sized mandrels 60. The upper surface 91 of the jaw actuator member and ~hose portions of the pivot pins 67 and 68 which extend into the actuator bore serve as means to retain the compression spring 92 in force applying relationship to the jaw actuator memher and through it to the j aws.
The coil spring S is shown in FIG. 1 to be supported at its lower end on the boss 100 formed on the handle 19 of frame 10. The boss extends into the lower ~urn of the coil spring S. A second boss 102 is provided in a recess 104 formed on the bottom of handle 11. The boss 102 like boss 100 fits into the end turn of the coil spring S. me maximum spread of the handles is limited by the maximum depth sleeve 6S may penetrate into chamber 51 in the head 15. In that position, the coil spring S is under compression and therefore it remains on the bosses 100 and 104 and holds the sleeve at its lowermost position. At the same time, spring 92 drives the actuator member 88 downwardly, as viewed in FIG. 5 to hold jaw pieces 78 in the open position.
In operation, when the actuating handle 11 is in the biased position raised upwardly from handle 10, sleeve 65 is moved downwardly to the position illustrated in FIG. 5.
Force applied by spring 92 through jaw actuator 88 maintains the jaws in contact with sleeve surface 72 and anvil surface 73. In this position, the jaws are spread out, the gripping channel 80 is widened and the mandrel slips reaaily into place as shown in FIG. 5. The application of slight pressure to squeeze handles 11 and 19 together raises the slee~e 65 sufficiently to cause the jaws to lock the mandrel and the . . .

rivet in place. This ~loaded" position prior ~o insertion of the shank of the rivet into the workpieces is a condition intermedizte between the two positions shown in FIGSo 5 and 6.
When ~he rivet is to be set, pressure is applied to handle 11 to overcome the coil spring S~ causing the handle 11 to pull the sleeve 65 with respect to the frame, and causing the jaws to grip the mandrel. This results first in deforming the shank to a somewhat flattened state 64 and ~hen in snapping the mandrel from the head. mrough proper alig~ment of the fulcrum locus (pivot pin 40) with respect to the pivot axis of pivot pins 67 and 68, the mandrel-pulling mechanism withdraws the mandrel in an essentially straight condition. mi5 in turn means that the mandrel is easily removed either by permitting it to fall out of the tool or by automatically discharging it into a mandrel collector. Stop 18 limits the ex~ent to which the handles may be forced toward each other, thus preventing injury to fingers which might be caught between the handles. The rivet mandrel may be then removed through the anvil bore or through the top of the sleeve.
It may be advantageous to be able ~o adjust, in any one tool, the amount of force which is applied by the jaws in ~ripping the mandrel. Thus if the mandrel is made of aluminum, this force is desirably less than if it is formed of, say, stainless s~eel or some other harder metal. ~n the case of a relatively ~soft" metal such a~ aluminum it is desirable ~o use less force to minimize the buildup of metal in the serrations of the jaws. Excessive metal buildup in these serrations requires that the jaws be replaced. In the case of the harder metals~ it is of course necessary to apply more force to assure gripping of the mandrel. The tool --10 - , .. . . . . . . . . .

modifications illustrated in FIGSo 10~13 provide means for adjus~ing ~he gripping force in addition ~o the in~erchanging of springs o various compressive strengths.
ln FIG~ 10, in which like reference numerals are used to identify like components in FIG. 5, the upper spring retaining means is a threaded ring 95 adapted to engage threads 96 cut within the inner wall of sleeves 65.
The position of ring 95 may be used to exert more or less compressive force on spring 92. me ring must have some way to engage a screwing mechanism for locating it into îts desired position, such as notches 97 ~FIG. 11). me pivot pins 67 and 68 may terminate within the sleeve wall as shown since they are not used as a spring-retaining means as in FIG. 5.
FIG. 12 illustrates the use of the ring 95 to adjust the gripping strength and the incorporation of a rivet collector 100 which for convenience may be joined to or integral with the ring 9S. In using tools to set rivets of the type described it is usually customary to permit the mandrels to fall ou~ of the tool into the work area. This is highly undesirable from the point of view of personal safety for they can cause serious falls when stepped on~ m e collection 100 of FIG. 12 prevents such hazards and may be used in one of two different modes. If a spring is used which has normal compressive strength, the mandrel may be collected by merely turning the tool over to permit ~he mandrel to fall freely into collector 100. The second proper location mode of operation is based upon the use of a weaker spring which, when the mandrel is snapped from the head, causes the mandrel to be impelled into the collector 100. The relative strength o~ the spring may be adjusted by the proper location of the ring.

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In the modification of FIG. 13, the pivot pins extend into the sleeve as in FIG. 13. These pins are used to engage one of a series of grooves 101, 102 and 103 in a ring member 104 which is adapted ~o fit into the sleeve an~ serve as the spring retaining means. By engaging the proper groove, a predetermined force is applied to the spring. There may~ of course, be any number of grooves or holes, and the ring 104 may be attached to or integral with a mandrel collector 105.
Coil spring S, by forcing the sleeve 65 forward, in cooperation with the action of ~he spring 92, assures that the jaw pieces open immediately upon release of pressure upon the handles. Consequently, no portion of the mandrel will become lodged in the head which may interfere with subsequent use of the tool. Furthermore, the strength of spring S is such that the handles are rapidly spread apart under its influence, and the sleeve 65 therefore moves rapidly in the head and jars the jaw pieces and other parts o the tool.
The resulting vibra~ion tends ~o shake loose any particles on the jaw pieces which may cause wear of the jaws. As a result, it is unnecessary to clean the interior of the tool as frequently as would otherwise be necessary. As yet another advantage, the automatic opening of the jaws eliminates the need for the user to operate the tool with two hands or awkwardly manipulate the fingers of one hand in order ~o open the tool for its next application. It should also be appreciated that the spring S may be incorporated into t~e tool structure without appreciably raising the tool costO These advanta~es are significant benefits derived from the present invention.
It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently a'ctained, and~ since certain chanyes may be made in the above apparatus without departing from ~he scope of the invention, it is intended 'cha'c all matter contained in th~ above description or shown in the accompanying drawin~s ~hall be interpreted as illustrative and not in a limiting sense .

Claims (3)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:-

1. A mandrel rivet-setting tool, comprising in combination a. a frame having a fulcrum member and an elongated finger engaging handle;
b. a chamber defined within a forward head extension of said frame, said chamber being open at the top and having a frustoconical configuration at its muzzle end which terminates in a threaded opening in said frame;
c. an actuating, palm engaging handle pivotally connected to said frame through said fulcrum member;
d. a sleeve defining therein an actuator bore, said sleeve being slideably movable within said chamber, said sleeve having an outer frustoconical configuration essentially corresponding to the configuraton of said chamber at its muzzle end and an inner lower frustoconical configuration;
e. an anvil having a conical contacting surface and a bore of a predetermined size adapted to permit the passage of the mandrel of a rivet therethrough, said anvil being threaded for screwing into the threaded opening of said frame;
f. a plurality of jaws within said actuator bore, said jaws when assembled having an outer surface configuration which essentially conforms to the inner lower frustoconical configuration of said sleeve and which define among them a passage adapted to grip a rivet mandrel, said jaws being cut to define upper and lower inclined planar surfaces, the upper planar surface slanting downwardly toward the central axis of said sleeve and the lower planar surface slanting upwardly to said central axis and being adapted to at least in part engage the conical contacting surface of said anvil;
g. a hollow jaw actuator member within said actuator bore and having a jaw-contacting surface adapted to achieve surface contact with said upper planar-slanting surfaces of said jaws;
h. means joining said sleeve to said actuating handle;
i. spring retaining means associated with the upper end of said sleeve;
j. a first spring within said actuator bore held in compression between the upper surface of said jaw actuator and said spring means for pushing the jaws against the sleeve to bias the jaws to a closed position;
and k. a second spring disposed between the handles and urging them apart so as to bias the sleeve toward away from the anvil and thereby overriding the first spring urging the jaw actuator against the slanting surface of the jaws and the lower slanting surfaces of the jaws against the contacting surface of the anvil to open the jaws rapidly when the handles are released and to jar the tool so as to vibrate it and shake loose any material which may stick to the jaws.

2. A mandrel rivet-setting tool as defined in claim 1 further characterized by said second spring being a coil spring acting in compression against the opposed surfaces of the handles.

3. A mandrel rivet-setting tool as defined in claim 2 further characterized by bosses provided on the opposed surfaces of the handles and extending into the end turns of the springs.