US2843174A - Rattle type dimple gun with tool and work heating means - Google Patents

Description

S. B. JONES July 15, 1958 v RATTLE TYPE DIMPLE GUN WITH TOOL AND WORK HEATING` MEANS Filed Jan. 21. '195s' H O H JNVENToR. .fria/wa 5. Jaw-'5 nited States Patent RATTLE TYPE DllVlllLE GUN WTH TL AND WRK HEATHNG MEANS Sterling B. Jones, Puente, Calif., assigner to Douglas Aircraft Company, luc., Santa Monica, Calif.

Application January 21, 1953, Serial No. 332,178

13 Claims. (Cl. EL3-21) This invention relates to lhand tools for use in hot dimpling apertures in sheet material While the latter is iixed in place on the structure of which it forms a part.

In contemporary hot dimpling, two men are required, one in front of the sheet and the helper behind same. The helper holds the back-up, or female, die against the sheet, either directly or my means of a bell bar which clears obstructions on the sheet-back while providing bearing and support for the back-up die. The man on the front of the sheet with one hand holds a male-die containing block heater against the hole and on the front tace of the sheet and holds the gun with the other hand, pressing its rattle-nose against the reciprocatable male die in the heater block. When the helper signals as above, the gun operator lires the gun, causing the male die to coast with the female die and form the dimple.

The heating dwell-period of such apparatus is of appreciable length unless the pre-pressure exerted by the gun holder is of considerable magnitude, so that either there is danger of underheating the sheet or of overtiring the gun operator and botching the work.

Since the dimpling gun incorporates a barrel for the dimple set or male dimpling die that is no wider or of no larger radius than that of the conventional riveting gun, it is ditlicult to maintain the sheet-contacting end face of this barrel in co-planar contact with the sheet, so that the axis of the dimple quite often cocks, or lies oblique to, the plane of the sheet. Such condition of course renders it impossible to properly seat a rivet in the dimpled rivet hole. V

Many of the newer metallic alloys incorporate characteristics which render their actions under heat ot diifering degrees unpredictable. Unless a constant quantity of heat of an adequate degree is employed with apertured sheet materials of this nature, the dimples in a single sheet will vary widely, some being too deep, some too shallow and many being cold-cracked.

The present invention provides a single, hand-held tool, which, in conjunction with a suitable source of compressed air, a source of electrical energy and a control panel for controlling these instrumentalities in proper sequence and degree, obviates, among other things, the long dwell-period and the high pre-pressure yet provides the requisite depth of dimple without danger of either cold-cracking or burning same. v

Only one hand need be employed by the operator, for no handheld, discrete block heater is utilized with the present tool.

in lieu of the small area of Contact provided by the operating head of the ordinary punch-die protruding unsupportedly from the barrel ot' the gun into engagement with the hole to be dimpled, resulting in cooking and ringing" of the dimple, the present tool provides a die-carrier therein which affords a large area of contact between the die, die-carrier and sheet, thus obviating cocking and ringing of the dimple. That is, the axis of lthe frusto-conical dimple is aligned with that of the rivet hole.

2,843J7 Patented July 15, 1958 r"ice Because of the fact that the tool enables a substantially constant temperature to be maintained in its heating components and in the die, the work sheet can be also maintained at a constant temperature. Hence, such relatively new aluminium alloys as ST, which are hard and unpredictable thermally, canY be as readily and accurately dimpled as those the thermal and metallurgical properties of which are well known.

Generally described, the tool provided by the present invention consists of a fluid-operated, hand-held heat applying and sheetdimpling .device comprising, essentially, a toolchassis or body made up, like a conventional rivet-gun, of a barrel-portion and a trigger-bearing handle portion configured together so as to define the general conformation of a pistol, the tool being of the Vibrator'y, percussion type or rattle type. A pressure-duid operated plunger unit is mounted coaxially in the barrel for reciprocation therein. For reciprocating this plunger unit', pressure-fluid conduit means are provided in the tool, the one terminus thereof lying operatively adjacent the rear end of the aforesaid reciprocatable unit, the opposite terminus of the conduit means being adapted for connection to a pressure-Huid source, the flow of pressure liuid to the plunger being initiated by a rattle timer in turn electrically connected in series with a trigger mounted on the handle of'the gun. A heat conductive male dimpling die is reciprocatably mounted coaxially of the barrel adjacent the forward end of the aforesaid reciprocatable unit.

Novel die-and-sheet heating means, taking the form of a massive, internally heated block-like nose portion of the gun, is'arranged in peripheral adjacency and in heat-transferring relationship to a portion of the die. The means for internally heating the block-like nose portion of the tool preferably consists of an electric heating coil including conductor paths extending longitudinally through the gun into connection with a pyrometer-triggered temperature controlling unit operative to maintain the block-like nose portion and the die at a constant temperature.

In use, the pilot-pin of the die, projecting forwardly from the block-heater, is inserted in the rivet-hole and the pre-heated die and block-heater, raised to a predetermined temperature before use and maintained at such temperature by the aforementioned control means. When the Templac on the back of the sheet in the vicinity of the rivet hole to be dimpled alters in the predetermined way at the predetermined temperature, the helper signals the gun-operator who then presses the trigger, causing the pneumatic instrumentalities to rattle the gun for a predetermined time at a predetermined rate, completing the dimple. Templac is a synthetic colored wax-like cornposition, usually in crayon form, which when applied to the sheet and when the latter is heated undergoes a characteristic change of color when said heat reaches a predetermined optimum degree. lt thus serves as a visual signal of the attainment of the proper temperature.

Most of those parts of the tool that are relatively susceptible to damage or to excessive wear and hence must be replaced more often than the other parts, are relatively easily accessible and those such parts which are not so readily accessible are so ldesigned as to be capable of withstanding the utmost stresses to which such parts are at all likely to bear. Withal, the article is so configured that it can be relatively inexpensively fabricated of simple and readily available materials.

By way of example, one of the presently contemplated embodiments of the inventive concepts is illustrated in the accompanying drawings and described hereinafter in conjunction therewith.

In these drawings,

Figure l is a side view, partly in longitudinal section, of the article also indicating its association with sources of electrical energy and pressure-fluid as well as the control means therefor;

Figure 2 is a front view of the article, and

Figure 3 is a fragmentary longitudinal section through the head portion of the gun taken to show a modified form of resilient restraining means for the die unit.

The construction illustrated in the drawings comprises, first, a substantially conventional rattle type, pneu i cally operated rivet gun 12 made up of a barrel portion 13 and a handle portion 14. Such guns are generally employed in the cold-riveting of alloy sheet metal and are universally employed in the airframe manufacturing industry as standard plant equipment.

A typical such gun, in fact, the one which was adapted to present purposes by merely replacing the pneumatic trigger and passage with the simple passage shown in Figure l, and then applying the heater head to the gun barrel, is known throughout the sheet-metal cetd riveting industry as the Ingersoll-Rand Companys AVC l2 rattle type rivet gun. The latter is fully disclosed iu the following pages from Ingersoll-Rand Companys Catalog, entitled Form 5606, August 1946, pages labelled Form No. 5661 and Exploded View. Clarnpcd to the outer end of the barrel, as by means of suitable releasable-type clamping screws 10, is a novel unit 15'. This unit is a combined male dimpling die set, and a heater for the die and for the Work area of the sheet to be dimpled and consists essentially of a rearwardl;l sleeved, block-like mass of thermally conductive metal. The sleeve 16 is hollow and bi-partite and the body 17 is also hollow, both longitudinal centrally and radially outwardly from this central region. Body portion 17 is substantially oval in front elevation, as shown in Figure 2, being enlarged along its vertical axis more than along the axis at right angles thereto.

In the handle 14 there is disposed a compressed-air conduit system 13 which leads in the conventional manner from a controlled source of compressed air, later described, to a completely conventional and well known, vibratory percussion type rivet gun including a well known rattle mechanism, not shown, in the gun and terminating forwardly in a headed shouldered, plunger 19. The rattle timer mechanism, as well as the pyrometer controlled electric switching mechanism, are of the conventional type made and sold by the Zephyr Manufacturing Company, Inc., Inglewood, California, and this switching means and timer are fully disclosed in their Catalog #14 of 1952, issued to the public by said company, in 1952, and detailed on pages 85, 88 and 89 therefore. Another headed plunger, 19A, is disposed coaxially forwardly of plunger 19 in the block 17. The gun barrel, here, is continued forward as an enlarged extension, B, having annular stop-surfaces 5t) and 6e, respectively. Plunger 19 works in the hollow forward end of the gun barrel as shown. The shoulder of plunger 19 bears against the annular stop-surface 56 shown when in its foremost position, and the head of plunger 19A also bears against an annular stop 6() as shown, when in its foremost position. To cushion the impacts of plunger 19 on plunger 19A, as Well as to assist in returning plunger 19A to its foremost position in the gun barrel, a light, coiled spring 21 is mounted on the rearwardly extending shank portion of plunger 19A. This springs rate is such that it can satisfactorily be overcome to allow the plunger 19A and the dimpling die, later described, to be moved rearwardly by the gun operators seating the dies pilot pin and head tightly in the rivet hole to initiate operations. The pneumatic pressure is so controlled by the conventional valve mechanism, not shown, in the gun as to cause the plunger 19 to reciprocate so as-to cause the plunger 19A to reciprocate the die unit, later dcscribed. To this end, the forward shank end of plunger 4 19A is passed thru heat-insulating rings 22, which block out heat passage to the guns handle, and thence into coaxial contact with the rear end of a punch-type male dimpling die 23. Die 23 consists of a pilot pin 24, a forming head 25, a forward shank portion 26, an annular stop 27 and a rearward shank portion 28.

The body 17 includes facewise abutted generally planeal and ovally contoured metallic members 29 and 31 of high specific thermal conductivity; a similar member 32 spaced longitudinally rearwardly from member 31, and the plurality of insulating sheets 22. All of these members have a substantially central aperture aligned coaxially with the axis of the gun barrel and are connected by bolts 35 to an annular flange 36 on the forward end of the sleeve member 16, to integrate same and support them on the gun barrel.

An electrical heating element, such as a Chromalox heater 37, is mounted in the space between members 31 and 32 and is disposed coaxially of, and lies radially outwardly spaced from, the central aperture of the head and from the plunger 19A. The terminals 39 of the electric heating coil are connected by means of series circuit establishing conductors 41 to a conventional pyrometer controlled source of electrical heating energy 54, which, in the conventional manner is switched on and olf by the pyrometer control so as to maintain the die and block at a constant temperature, for example, for dimpling 75ST, of the order of 600 C. A conventional pyrometer controlled, on and olf electrical current switching system employable herein in this connection is made and distributed by Zephyr Manufacturing Company, Inc., Inglewood, California, and is fully disclosed in Catalog #14 of Zephyr Manufacturing Company, Inc., Inglewood, California, issued to the public in 1952; see pages 85, 88 and 89 thereof.

Between the front face of heating element 37 and the rear face of the hollow annular plate-like member 29 (and unit 31) is interposed a metallic, annularlyflanged member 86 serving with 32 to hold the heating element 37 while transmitting heat therefrom to the member 24, via the intervening metallic elements shown. That is, members 29, 80, 37 and 32 constitute the group the exterior surface of which is labelled 31. 31 in effect, therefore, constitutes a multi-part plate-like unit.

The front face of unit 15 consists of a reciprocatable piate 43 of generally rhomboidal shape and having a central aperture bearing a longitudinally inwardly extending sleeve 45, the sleeve being seated in the central aperture in plate 29. A reciprocatable tie-member 46 extends from each of the opposite ends of the plate 43 through the members 29 and the remainder of the group the external face of which is designated 31 and into rearwardly extending-sleeves 47 that are integral with plate 29 and pass rearwardly through the insulating sheets and the flange 36. The heads of members 46 bear on the front face of plate 43 and the rearward end of each of the Shanks of these reciprocatable members includes a radial enlargement 49 which slides in a bore 48A formed in a member 48B fixed in place and having a hollow center thru which 46 can slide, so as to guide and restrain the tie members 46 in their movements. In order to absorb or reduce the vibratory displacements of the various forwardly and backwardly reciprocatable parts of the tool, including those of the plungers transmitted through a cup like member 52 to the plate 43, a coiled spring S1 is interposed between the washer-faced member 48A and the shoulder 49 and S0. This spring absorbs the rattle shocks of the gun and the washer restrains forward movement of the die, thru the intermediacy of the ties 46, plate 43 and cup 52 and returns all the aforesaid parts gently to their rearmost positions at the end of the forward stroke of the rattle mechanism, thus minimizing the vibrations of the gun.

The cup-like member 52 is disposed in the central aperture of members 43, 29 and 31 and lies coaxially around the dimpling die, supporting the shoulder of the die and seating on the sleeve of plate 43 as well as on plates 29 and 31. Member 52 terminates rearwardly, as shown, in an annular flange 53 which in turn is engaged against the sleeve of plate 43.

Thus, reciprocation of the die is guided and restrained for centered, non-cocked rattling thereof, the reciprocating movements of the die being restrained and guided along a line which is an exact coaxial prolongation of the axis of the rivet hole.

Substantially all the heat generated in the coil 37 is transferred to the die and to the cup 52 and thence to the work-area by contact of the front face of the cup therewith. For, heat transfer to the gun barrel is substantially prevented by the insulators 22 and the radiating ns on sleeve 16, and the members 31, 29, 43 and 52 are all of high thermal conductivity. A large heat head is built up in the block 17, which acts as a sort of heat capacitor. Once this block has been raised to the operating temperature of around 600 C., which requires a period of the order of 24 minutes, it is maintained there by unit 54 as long as the electrical energy source is connected to the gun.

A source of compressed air, controlled by a suitable rattle timer, both in the block indicated by reference numeral 55, is provided for enabling actuation of the gun when the helper signals that the Templac has altered indicatively yat the predetermined temperature. As is well and universally known, Templac is a synthetic preparation employed in hot dimpling on the back side of the work sheet around the rivet hole and is subjected to temperature rise from the hot dimpling die so as to indicate, by changing from its original color into another characteristic color, that the sheet has .attained the optimum tempertaure for hot dimpling. The rattle timer of unit S is connected in series to the switch 42 by the conductors SSA in such a manner as to eect opening of the control valve at the compressed air source when the closing o-f switch 42 closes the circuit to the rattletimer. The ensuing'rattle usually consists of l5 strokes completed in a few seconds. At the end of this predetermined time, pre-set on the rattle-timer, the timer Opens the electrical circuit, closes off the compressed air, `and halts the operation of the gun.

In Figure 3 there is shown a modiiication of the means for movably uniting the plate 43 to the remainder of the unit 15. This modiiication is designed to provide greater ilexibility in this connection so that any eccentricity in the reciprocating movement of plate 43 can be accommodated by the lengthwise flexing of the tie rods 46A, thereby to obviate breakage or binding of these connecting members when and if the plate 43 is recprocated eccentrically by the die-supporting cup, or if the enlargement 49, or the shank, should happen to bind or stick in their supports. f

To this end, and others, the novel construction of Figure 3 includes, in lieu of the tie-members 46 of Figures l and 2, a connecting-member 46A consisting of a head 61 having a shank 62 adapted to tit loosely in a bore 63 in plate 43; a main shank 64 terminated rearwardly by a radial enlargement 49 and passing through a collar 66 xed by its outer periphery to sleeve 47. Between the collar 66 and the enlargement 49 there is disposed a coil spring 67 for restraining forward movement of the tiemember and plate 43 yand for 'automatically returning the plate and the die unit to their original positions.

Between the rear end of the shank `62. and the forward end of shank 64 `there is Iinterposed a pair of longitudinally extending, pivotally united chain links 68, the forward and rear ends of which pair are pivotally connected respectively to the shank 62 and the shank 64.

Thus, if the lower end of plate 43 should -lie out of the 'same vertical plane that includes the upper end thereof, that is, if plate 43 should become cocked or if the ports, the link-unit will buckle and absorb this unbalanced thrust and remove this force from the remainder of the unit, straightening out and eliminating the cocking yand binding when the direction of Ithe force is reversed.

By virtue of the combination of the heated punch type die and the very efficient generation, of heat and its direct transfer `and application in a concentrated manner by the massive skirt of the die-unit constituted by the block-heater, the heat-capacitor effect created at the front end of the kunit concentrates substantially all the heat generated by the coil and directly applies it to the sheet around the rivet hole instead of its being largely dissipated as with the conventional hand-held block-heater. Thus, a deeper and better dimple can be obtained in -a given -dwell-time and with less pressure.

The outer face of the cup-like die support is flat and relatively broad, so that the nose of the tool has a wide smooth, planeal bearing surface in contact with the work sheet. Hence, it is substantially impossible `to cant or tilt the die with respect to the rivet hole and cock-ing of the dimple, hitherto due lto canting of the gun around its narrow nose, is prevented. By the same token, the sheet is contacted with equal force all around the rivet hole and the faying surfaces are congruent, sothat ringing of the sheet is prevented.

Since the unit l5 can be readily detached from the remainder of the gun and disassembled into its components very easily, the electrical components can be separately removed for servicing by electrical personnel, leaving the pneumatic components 13 and 14 for servicing by speciali-sts in this field.

Those parts, such as the cup and the plate 43, which are rather more susceptible vto wear or damage than the other parts, are obviously readily accessible for removal yand repair.

Although the parts and configurations of a certain one of the presently preferred embodiments of the invention have 'been described with reference `to specic shapes, compositions, etc., it is to be understood that this has been done merely in order to render the inventive concepts more concrete `and in no manner constitute the sole form in which these concepts can be embodied. In fact, and in l-aw, the invention is limited in the for-ms which it can assume only by the lscope of the subjoined claims.

1 claim:

l. A fluid-operated hot-dimpling tool for dimpling in -situ an aperture in a xed sheet, compri-sing: a main body including a barrel portion; fluid-reciprocatable actuator means disposed coaxially of said barrel portion; forwardly. and backwardly reciprocatable supporting means constituting the forward portion of the tool; a heat-conductive male dimple die retract-ably and protractably mountedin said reciprocatable supporting means and lying c0- ax1allyof said actuator means that are in said barrel portion wlth its rear portion coaxially adjacent the forward end of said actuator means; heat-generating means disposed coaxially of the forward end of said barrel pornon and lying radially outwardly of said actuator means andlsaid die; and massive, thermally conductive heat transferring means disposed radially and longitudinally in supporting relationship to said actuator means, die and heatgenerating means, the rearward portion of said heat transmitting means being supported by said barrel, the forward portion of said heat transmitting means being resiliently connected to the rearward portion of said transmitting means and carrying said die with it in its reciprocaton by said actuator, whereby to enable said die to be manually applied to said aperture and said sheet so as to 'heat same to enable integrative, or crackless and ringless, dimpling of same, upon reciprocation of said actuator-unit.

2. A fluid-operated hot-dimpling tool for dimpling in situ an lalgierture in a fixed sheet, comprising: a main body shank 64 or enlargement 49 should bind in their sup- 75 including Va barrel portion; tluid-reciprocatable actuator means disposed coaxially of said barrel portion; forwardly and backwardly reciprocatable supporting means constituting the forward portion of the tool; a head-conductive male dimpling die retractably and protractably mounted in said reciprocatable supporting means and lying coaxially of said actuator means that are in said barrel portion with its rear portion coaxially adjacent the forward end of said actuator means; heat-generating means disposed coaxially of the forward end of said barrel portion and lying radially routwardly of said actuator means and said die; and 'block-like mass of heat receiving material carried by said barrel and having an `effective dimension lengthwise of the die not substantially less than its effective dimension transverse of the die, said mass having `a forward portion and a rearward portion, the rearward portion ot said mass being fixedly supported bythe front end portion of said barrel `and the forward portion of said mass being resiliently connected to said rearward portion of said mass, said forward portion carrying `the protractably and retractably mounted die with it in its reoiprocation by said actuator, said mass `being disposed in heat receiving relationship to said heat-generating means and `in heat-transferring relationship to said die and `adapted for heattransferring contact with the sheet to be dimpled, the reciprocatable die normally protruding from the forward face of said mass whereby to `enable said die to heat said sheet around said aperture, to enable craclrless and ringless dimpling of same, upon reciprocation of said actuator-unit.

3. A fluid-operated hot-dimpling tool for dimpling in situ an aperture in a fixed sheet7 comprising: a main body inclu-ding a barrel portion; uid-reciprocatable actuator means disposed coaxially of said barrel portion; a heatconductive male `dimpling die disposed coaxially of said barrel portion with its rear portion coaxially adjacent the forward end of said actuator means; heat-generating means dispo-sed coaxially of the forward end of said barrel portion land lying radially outwardly of said actuator means and said die; and massive, lthermally conductive means disposed radially and longitudinally in supporting relationship to said actuator means, die, and heat-generating means, and tixed at its rear end to the front end portion of said barrel with said die protruding from the forward face of `said mass whereby to enable said die to be applied to said aperture and said sheet so as to heat 1- same, to enable crackless `and ringless dimpling of same, upon reciprocation of said actuator-unit, (said thermally conductive means supporting an annular die-retaining member disposed coaxially in contact with the forward end of said die, said iannular member having an outer planeal face adapted to iit congruently and substantially coplaneally against the face of the sheet to be dimpled thereby to prevent eockingand ringing of the dimplc.

4. A uid-operated'hot dimpling tool for dimpling in situ an aperture in a fixed sheet7 comprising: a main body including a barrel-portion; uid-reciprocatable actuator means disposed coaxially of said barrel-portion; Ia heatconductive male dimpling die reciprocatably mounted in said tool coaxially of said barrel-portion with its rear portion lying coaxially `adjacent the forward end of said actuator mea-ns; heat-generating means disposed coaxially of the forward end of said barrel portion and lying radially outwardly of said actuator means and said d-ie; massive thermally conductive plate-like members having open central portions disposed coaxially of the barrel end and united thereto; heat generating means mounted on the rear face of the rearward one of said plate-like members, said means lying radially outwardly of said die and said actuator means; radially extending heat insulating means disposed blockingly rearwardly of said heat generating means and united to `said barrel; and means carried by said plate-like members for supporting said die for reciprocation coaxially of said barrel, said supporting means and said plate-'like members lying in heat-transferring concentricity with said die so as to transfer `substantially all the heat-generated by said heat-generating means to said die and to the front-portion of said tool.V

5. A fluid-operated hot-dimpling tool for dimpling in situ an aperture in a iixed sheet, comprising: a main body including a barrel portion; iiuid-reciprocata'ble actuator means disposed coaxially of said `barrel portion; a heatconductive male dimp-ling die disposed coax-ially of said barrel portion with its rear portion coaxially adjacent the forward end of -said actuator means; heat-generating means disposed coaXially of the forward end of said barrel portion and lying radially outwardly of said actuator means and said die; and massive, thermally conductive means disposed radially and longitudinal-ly in supporting relationship to said actuator means, die, and heat-generating means, and xed at its rear end to the front end portion yof said barrel with said die protruding from lthe forward face of said mass whereby 'to enable said die and said thermally conductive means to be applied to said aperture and said sheet so as to heat same to a predetermined degree before reciprocation of said actuator-unit, said massive means including an annular die-retaining member disposed coaxially in contact with the forward end-portion of said die, said annular member having an outer planeal face adapted to tit congruently and substantially coplaneally against the face of the sheet to be dimp'led, said die-retaining member having an annular outwardly extending flange on its rear portion; la reciprocatable supporting member disposed coaxially of said die and retaining member, said supporting member extending radially outwardly of said annular member and having a central portion engaging lthe flange on said die-retaining member; and means carried by Vsaid massive means and extending longitudinally of said barrel, for resiliently connecting said supporting member to said mass, thereby to enable said supporting member to be tted cop'laneally against said sheet and to reciprocate substantially parallel to the `barrel with said -die `and retaining means.

6. A heating device adapted for attachment to the front end lof the barrel of a vibratory, percussion-type riveting gun which is outwardly terminated by a coaxially reciprocatable die-actuator unit, said gun including a trigger-controlled electrical circuit adapted for attachment to a rattle-timed uid energy source, comprising: a main body including a barrel-portion, a centrally hollow, block-like mass of thermally conductive material, the rear-face of said block including a rearwardly extending prolongation adapted for attachment coaXially to the barrel end; means for re-leasably attaching said prolongation to the forward portion of said barrel; a fluid-reciprocatab'le actuator unit disposed coaxially of said barrel; a heat-conductive male-dimpling die reciprocatably mounted in said block-like portion coaXially adjacent the forward end of the actuator unit thereof; and heat-generating means mounted in said block-like portion in heattransferring relationship thereto so as `to effect concentrated heating of said block-like portion and said die, said heat-generating means including means adapting same for operative connection to a source of heating energy for maintaining said block-like portion at la constant temperature.

7. A hot dimpling tool for dimpling 'a rivet hole in a fixed sheet, comprising the combination of: a 1fluid-pressure operated vibratory percussion type riveting gun that includes a barrel coaxially carrying a fluid pressure reciprocated die-actuator means adapted to be operatively connected to a source of fluid pressure; with: heat-generating `and accumulating means carried vby the end of said barrel, the heat generating and accumulating means vbeing substantially a unit and comprising 'a rearward portion xedly attached to `the barrel and a `discrete forward portion resiliently connected to said rearward portion; a male dim-pling die reciprocatably disposed coaxia'lly of the reciprocatable 'forward portion said heat generating 9 and Iaccumulating means and protruding from the forward portion thereof; and discrete thermally conductive die-supporting means reciprocatably mounted coaxially of said heat-generating and accumulating means and supported coaxially in said reciprocatable forward portion of said means and disposed in 'heatareceiving relationship to the heat generating means and disposed in heat-transferring :relationship to said die for supporting said reciprocating die while concentrating substantially all the heat gener-ated in said tool on said die and on the work-area of `said sheet.

8. A hot dimpling tool for dimpling a rivet hole in a fixed sheet, comprising the combination of a fluid-pressure operated vibratory, percussion-type riveting gun that includes a barrel carrying fluid-pressure reciprocated actuator means adapted to be operatively associated with a source of pressure uid; with: a block-heater unit carried by the end of said barrel, said heater unit comprising a rearward portion fixed to the barrel and a discrete forward portion reciprocatably connected to said rearward portion; a rearwardly concave male-die support retractably and protractably mounted coaxially in said discrete forward portion, said die-support having a planar outer face which is substantially wide relative to the barrel-diameter said face being adapted for facewise congruent contact with the work area around the rivet hole, so as to prevent cooking and ringing of the dimple; a dimpling die mounted coaxially in said die-support and adapted to be seated coaxially of said rivet hole by said congruent contact of said face and said support; and means mounted in said block for heating said die and said block thereby to enable same to heat the work area to a predetermined optimum temperature before reciprocation of said die thereagainst.

9. A fluid-operated, sheet-dimping tool adapted to be connected to `a constant temperature-maintaining source of heating energy for in situ hot dimpling of a perforate area in a fixed sheet, comprising: a tool body including a barrel portionand a trigger-bearing handle portion; a pressure-fluid operable reciprocatable actuator unit mounted in said barrel; fluid conduit-means in said tool having the one terminus thereof disposed operatively rearwardly adjacent the rearward end of said actuator unit and having an opposite terminus adapted to be controllably connected to a pressure-fluid source; a heatreceiving and transmitting male dimpling die disposed coaxially at the foremost end of said tool operatively adjacent said actuator unit; a massive heat receiving and transmitting group for heating said die, said group comprising a rearward portion fixed to said barrel and a discrete forward portion reciprocatably -connected to said rearward portion, said male die being protractably and retractably mounted in the reciprocatable forward portion of said massive unit and in heat-transferring relationship therewith; electrical energy conductor paths carried by said tool and connected at the one end to said die-heating means and having the opposite end adapted for connection to said heating-energy source so as to definev a circuit with said heating means; and normally inactive control means arranged in the tool and adapted to be closed to effect energization of said actuatorunit.

10. A tool, comprising: a tool-body that includes a barrel-portion and a trigger-bearing handle-portion; an actuator-unit reciprocatably mounted coaxially of said barrel; means 'for reciprocating said unit; a heat-receiving and transmitting male dimpling die disposed coaxially at the foremost end of said tool operatively adjacent said actuator-unit; and a massive heat-capacitor means for heating said die, said capacitor means comprising a rearward portion fixed to said barrel and a discrete forward portion reciprocatably connected to said rearward portion, said male die being retractably and protractably mounted coaxially in said reciprocatable forward portion of said capacitor; and heat-generating means carried by said barrel and actuatedrby said trigger; said capacitor being arranged in heat-receiving adjacency to said heat-generating means and in heat-transferring relationship tosaid male die for concentrating substantially all the heat generated by said heat-generating means, said capacitor means being disposed radially adjacent said die and adapted to apply substantially all said concentrated heat to said die.

1l. Means for hot dimpling in situ an aperture in a fixed sheet, comprising: a hand-held tool comprising a barrel-portion and an actuator-unit mounted coaxially in said barrel; means for reciprocating said actuator-unit; a heat-receiving and transmitting male dimpling die disposed coaxially at the foremost end of the tool operatively adjacent said actuator-unit; means for generating dimpling heat radially adjacent said die and in a location lying entirely on the same face of said sheet as does said die; means for accumulating said heat in a zone lying radially adjacent said die and lying in facewise adjacency to the same face of said sheet on which said die lies; said heat accumulating means comprising a rearward portion fixed to said barrel and a discrete forward portion reciprocatably connected to said rearward portion and loosely carrying said male die coaxially thereof; and means for applying said heat to the aperture and work-area from said die so as to enable crackless and ringless dimpling of same.

l2. A fluid-operated, hot dimping tool for dimpling in situ an aperture in a fixed sheet, comprising: a fluidpressure operated vibratory percussion type riveting gun that includes a fluid-pressure reciprocated actuator unit projectable therefrom and adapted to be operatively associated with a source of pressure fluid; a heat-conductive male dimpling die disposed coaxially operatively ahead of said actuator unit; rearwardly and forwardly located, transversely extending, centrally apertured thermally conductive members the rearwardly located members being unitarily attached to the front end of said gun and the forward thermally conductive member being discrete and reciprocatably connected to the fixed rearward members and the forward members bearing a central aperture for receiving said die in the central aperture; heat-generating means mounted in heat-transferring relationship to the rear face of the discrete reciprocatable member of the unit of thermally conductive members; and an annular, thermally conductive discrete diesupporting member arranged in heat-transferring relationship around said die, said die-supporting member being reciprocatably supported in said central aperture and having a planeal front face adapted to bear congruently and heat-transferringly on the work-area surrounding said rivet hole.

13. In a dimpling tool for use in situ on an aperture in a sheet on a framed structure, and including a body having a barrel-portion: a reciprocatable male die disposed coaxially of said barrel; means for reciprocating said die; heat-generating means disposed coaxially contiguous to said die; a heat-accumulative mass concentrated coaxially around said die and said heat-generating means; and die-retaining means disposed in coaxial contiguity with the die, said die-retaining means having an outer planeal face adapted to fit facewise against the face of said sheet; said die-retaining means having an outwardly extending flange on its rear portion; reciprocatable supporting means disposed coaxially of the outer end of said barrel-portion and operatively engaging said flange, said supporting means being adapted to fit facewise against said sheet; and resilient means connecting said supporting means to the concentrated mass so as to enable said supporting means to reciprocate with said die and die-retaining means.

`(References on following page) UNITED STATES PATENTS Putnam May 23, 1899 Cox Dec. 2, 1919 5 Rechton et a1. Mar. 27, 1945 Kahler et al. Apr. 17, 1945 Haberstump Mar. 26, 1946 Yanchenko July 15, 1947 12 Schwartz Nov. 16, 1948 Marik Oct. 24, 1950 OTHER REFERENCES The disclosure on pages 213 and 214 of Metal Industry for September 13, 1946.

The disclosure on pages 25 and 26 of the Journal of Aeronautical Sciences, vol. 18, No. 1, November 1940.

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