US2544326A - Surface finishing ironing tool - Google Patents

Description

March 6, 1951 w. c. JONES SURFACE FINISHING IRONING TOOL Filed July 8, 1947 MM Wd c5 M M MW Patented Mar. 6, 1951 UNITED STATES PATENT QFFICE 2,544,326 SURFACE FINISHING IBQNING T9013 William Jones, Oalrland, Calif. Application July s, 1947, serial NQ. 759,560

g claims. (c1. g1g-2i) This invention relates to electrically-heated tools for Working thermally ductile materials and, more particularly, relatesI to improvements over the structure shown in my previous Patent No. 1,787,866, issued January 6, 1931.

An object of the invention is to provide a tool of the character described having a plane ironing surface so arranged with respect to an associated electric heating element that the heat conf ductance path from the heating element .to the ironing surface is reduced as much as possible so as to .bring the latter surface to proper oper;- ating temperature in a minimum of time.

Another yobject of the invention is to provide an electrically-heated tool of the type referred to in which the flat ironing surface is constantly maintained at .a pre-heating temperature con,- siderably above normal room tempeliiillre Ymit still below l.that sucient to prevent scarring Jci fusible surface materials with which the tool may accidently contact, (and in .which vprcwision 4is made .to elevate the ironing surface yto materiale fusiontemperature `at theselection of the oper,- ator.

A further object of .the invention is .to provide, in a tool of the class described, a .readily ,removable headpiece of .generally pointed form containing a heating element and contact mem#- bers through which current may be conducted from the main body of the tool .to the heating element, the heating element being so l,arranged that the at .ironing surface ,of the headpiece, even to the .extreme ,tip thereof, will ,be rapidly and vsubstantially uniformly heated.

Still another object of ithe invention is tto provide,in conjunction with a detachable ,headpiece for a tool of the type referred Ito, simple `and effective means Vvfor locking the .headpiece `,to Y tljle main body portion of the tool so that relative separation of the headpiece and main body portion ymay not accidently occur during v,normal us;- age of the tool.

Yet another objectof the-invention is to provide in a device of Athe character described, sep,- aratecontroiswitohes fior regulating .current flow to the heating element .which may-bo operated singularly or plurally .to yproduce a .variable thermal y.output Kin .the 1lfieating element; the ,switches being veapableroi actuation by a single hand ,of the operator .which also ,omnloredirimanipulating the tool.

li .is oiioiiior Loloiooi of the invention to lorovide a heated headpie'e lfor a tool "of the aboveiosoriloed Character in whioh orovisioiiis modo io trop amorosi/oy io tho iiai 'iioiiiii'g viir'faolfi of the hoaooiooo the marmimi omoiirli ofhoat oriiiiioii Joy the hosting element ooiiinodihoro- 1n.

It .is a further object of the iiiioiiiioii oo Provide in a shell-typo hoadpiooo. .fof a tool .of tho class referred to, which is provided with on eleotrio heating ,element tborowiihin, moans ,for ,rosilieiitly wedging the heatingolemoiit into the headpeoe ASopas ,to effect continuous firm Contact of the ,heating element .with the wall portion of the ,shell Subjaoent .to ,the hat ironing A,Siiifaoo to insure that heat is transmitted to the latter surface over the shortest possible transmission route.

It is still another object o the invention to provide, in a tool of .the character described, a headpiece including a single-circuit heating element'contr'oll'able `by lmeans disposed for .the most part exterior-ly of ,the .tool to variably heat the iheadpiec'e and serving .to reduce toa mini'- mum the bulkiness of the tool which would be greatly increased if lthe entire control mechanism Was contained Within the body `of the'too'l,

The' invention vpossesses other objects and features of advantag'efsmevof which, with the fore- 'goin'gfwll'be set forth in then following'description of the preferred form ofthe invention Which is illustrated in the' dravvings'accompaiiying and forming part of Athe sp'eciii'cation'.`V It isl to be understood; hovvever"', that variations inthe show- ,ing made 'by fsaid drawings andde'sc'rip'tion may be gnomepl fwnningtn scfdpe if the inventan as stfoiu'in the claims?" Referringftb trie drawing:

'Figure liis/A a 'terspoot've `View ,of tho improrod ironing'ltoolof vention-` "Figure lor ical' Sectional View taboo .in a plane'extendmg florieitiidi-inal11ifof ftlifo ,Sltiiotiilo 'of Figure Figure `3' is an enlarged vertical sectional view taken in the VVpian i'oaied ,lov ihoiliiioS-iof Figure?. L Figure l'i is anvenlarged perspective View of the terrrinil end heit i1 'di 'the jfollootio heating imit- Y,Figure 'is etileno' 2, the terminals being shown in relatively disengaged positions.

Figure 6 is a circuit diagram showing the relaticnship and the connections between the various electrical components of the apparatus.

Figure 7 is an enlarged vertical sectional View of a portion of the headpiece showing a modified form of my invention.

Figure 8 is a perspective View of one form of headpiece.

Figure 9 is a perspective view of a modied form of headpiece.

In carrying out my invention, I provide a cylindrical grip or handle, preferably constructed of wood or molded of any of the synthetic resins, which comprises a pair of juxtaposed sections 8 and 9 secured together by transaxially extending screws II or in any other suitable manner. Substantially centrally of the handle, I provide a chamber I2, composed of registered recessed portions of each handle section, in which is contained a current control switch I3 preferably of the single-pole single-throw snap type having a control rod or elongated push button I4 slidably extended through suitable transaxial apertures i3 provided therefor in the handle sections. The switch I3, it will be seen, may be selectively turned on or oil by movements of the operators hand grasping the handle. Also provided in the handle and extending along the parting plane I1 thereof, are bores I8 and I9 the former of which is circular in cross-sectional form and the latter of which is shaped as the chordal segment of a circle, one side being iiat and inserted by a curved opposite side whose center of curvature lies beyond the flat surface and exteriorly of the area enclosed by the flat and curved surfaces. The exact contour just described is illustrated in Figure 3 of the drawing.

Disposed in the bore I9, and extending beyond the end of the handle, is a tubular metallic shank 2I complementary in cross-sectional form with the bore. I9 and secured in the latter by means of one of the screws II which passes vertically through the shank. Within that portion of the shank resting in the bore I9, I provide a control switch having a base block 22 of synthetic resin or the like on which is mounted a xed contact 23 and an overlying ilexible contact arm 24 normally held out of engagement with the contact 23 but engageable therewith when flexion pressure is applied to the arm.

Means for applying such pressure is provided in. an axially slidable push rod 26 mounted in the y handle overlying the Contact arm 24 and provided with an externally exposed push button 21 capable of being depressed by the thumb or a finger of the operators hand grasping the tool handle. The outer end of the shank 2l is cut off diagonally to form an overhanging lip 28 having an aperture 29 and within the end of the shank is provided a block 3| of electrical insulating material having therein a pair of separate contact sockets 32 clearly shown in Figure 5.

I provide a headpiece or ironing tip, examples of which may be seen in Figures 8 and 9, for detachable connection with the tool shank. These headpieces may be made in various forms for use in accomplishing various nishing jobs, 1

such as the rounded and spade points shown, but each comprises an outer sheet metal shell 33 having therein an open-ended recess 34 and provided in its upper arched surfacewith an upwardly pressed protuberance 36 complementary with and adapted for engagement in the aperture 29 of the lip 28. The lower outer face 31 of the shell comprising the ironing surface is ilat over its entire extent but has its distal portion adjacent the tip, as shown in Figure 2, curved upwardly so as to facilitate accommodation of the tool to work on fiat or slightly concave surfaces.

In the recess 34 of the headpiece is disposed an electrically energized heater preferably comprising a center strip 38 of mica, pressed asbestos board or the like, having at one end a pair of separate keyhole-shaped notches 39 and further provided with integral tongues 4I or the like upon which is wound a unit length of chromenickel alloy wire 42 whose terminal end portions 43 are engaged in the apertured head elements 44 of terminal lugs 46 registered with and adapted to enter the recesses 41 of the sockets 32 so as to establish electrical contact with the latter. The lugs 46 and the center strip 38 have corresponding vertical thickness. The head elements 44 and the immediately adjacent shank portions of the terminal lugs 45 are shaped correspondingly with the keyhole shaped notches 39 and lit snugly therein, as shown in Figure 5, so as to lock the terminal lugs in the center strip 38. Overlying the upper and lower surfaces of the center strip and its attached terminal lugs, I provide sheets 48 of mica or the like heat-resistant and electrical insulating material and encircling the assembly is a metal sheath 49 whose opposite wing portions 5I are left projecting angularly fromfthe uppermost sheet 48 as will be seen in Figure 3. `When the assembled heater is pressed longitudinally into the lengthwise tapering recess 34 of a headpiece, the wings 3| will engage the inner sloping surface of the arched upper member of the shell thereby flexing the ears downwardly and forcibly pressing the heater against the lower flat wall of the shell above the ironing surface 31. As a means for locking the heater in the headpiece shell so as to forestall possible dislodgement of the former 4.1 due to abnormal tensile strains which may be exerted on the lugs in the process of detaching the headpiece, I provide an ear 52, shown in Figure 4, preferably formed integrally with the sheath 49 and bent upwardly between the lugs 4G to overlie the end surfaces of the stacked insulating strip and sheets 33 and 48 respectively. After the heater has been properly positioned the shell recess 34 may be lled with porcelain cement or the like heat-resistant substance.

Attachment of the headpiece to the main body portion of the tool may be effected by bringing the former into proper alignment with the latter, as regards the relative cross-sectional forms thereof, and pushing the headpiece toward the end of the tool which will cause the lugs 46 to enter the recesses 41. As the lugs approach their fully inserted positions, the protuberance 36 approaches and passes under the outer extremity of the lip 28 which will thereby cause a slight downward flexing of the lugs. Thus, when the protuberance 36 comes into registry with the aperture 29 the former will snap into the latter and thereafter securely lock the headpiece to the tool body until forcibly and deliberately released. Since, during normal operation of the tool, pressure of the headpiece will be exerted downwardly against the work surface, the resultant upward pressure against the flat ironing surface 31 will further tend to retain the protuberance 36 in engagement with the locking aperture 29.

21,544, aac"A Associated with the tool I provide a current supply cord preferably composed of three conductors 53, 54 and 56, the former of which mayv be attached to one terminal. lug 51 of a plug connector 58 and the latter two of which may be attached to the other terminal lug 59 of the plug connector. The conductor leads to one terminal of the switch I3 and from the other terminal of the latter switch to connect with a terminal end of the heater winding 42. The conductor 56 is connected to one terminal 24 of the push button control switch, the other terminal 23 of. which is. connected with the remaining terminal end of the heater coil. 42. The conductor 54 either comprises or has built thereinto a current limiting resistor 6l the terminal end of which is connected to the switch contact 23 or the conductor permanently connected therewith. Operation of the tool is effected by attaching the plug connector 58 to a suitable current outlet and closing the switch I3. This causes current to fiow through the heater coil 42` at a reduced rate due to the presence of the resistor 6I in the conductor 54. When the push button 21 is also depressed to close the contacts 23 and 24, the resistor 6I will be shunted and full current fiow will occur in the heater coil. The circuit design is such that under full current load, with both switches closed, the heater coil will generate sufficient heat to create a temperature in the ironing surface 31 of the headpiece which will cause desirable softening or complete melting of the fusible finishing materials which will be described presently and with which the present tool is adapted for use. Opening of the switch contacts 23 and 24, by the removal of iinger pressure from the push button 21, will reduce current ow to the heater coil so that the ironing surface may cool to a temperature somewhat below the fusion temperature of the aforesaid iinishing materials. The tool is therefore always kept in a preheated condition at a reduced temperature and may be more rapidly brought to full operating temperature, when such condition is required, than would be the case if all current flow to the heater coil were shut off.

In Figure 7 I have shown a modified form of headpiece designed to concentrate as much as possible of the heat generated by the coil at the flat ironing surface. Here I have shown the lower portion 62 of the shell as a separate fiat plate on which is formed a plurality of relatively spaced transverse ribs 63 about which is wound the coils 64 of the heater, the latter being embedded in poreclain cement 66 or the like for electrical insulation from the metal headpiece. The crowned upper plate 61 may be secured to the lower plate along its margin by brazing 68 or the like. Heat from the coils will be radiated into the ribs 63 which will conduct it to the bottom plate 62 and thence to the fiat ironing surface 69.

I'he widest field of use for the tool of my invention lies in the finishing of furniture or the like wherein suitably colored, heat fusible substances such as rosin, certain of the synthetic resins and the like are used as fillers for cracks, surface nicks and other imperfections which would mar the appearance of the finished product. Most of the substances useful for this work have melting points of about three or four hundred degrees which means that the ironing surface of the tool must be brought to or above the larger temperature to work properly. Obviously, to maintain the tool at such an elevated temperature during times when the tool is not in or effecting severe contact burns on the person of the user should the latter accidently brush against or grasp the heated tool. By providing for immediate reduction in current flow tothe heater coil, when the tool is momentarily set f' aside between the numerous applications of filler material which are necessary in the average finishing or refinishing job, thedangers of burning or scarring of the person of the operator or of highly finished surfaces on which the tool may be placed are reduced to an absolute minimum since with the resistor 6| in circuit with the heater coil, the temperature of the ironing surface may not exceed about one hundred degrees which renders the tool incapable of causing the aforesaid damage. However, since the tool is maintained at the lower temperature as long as the switch I3 is turned on and current is being supplied to the conductors 53, 54 and 56, as soon as the contacts 23 and 24 are closed by pressure on the push button 21, the heater coil temperature'will, in a matter of seconds, rise to the higher operating temperature. During the course of actual application and smoothing of the fusible finishing material the heat at the ironing surface will be under the full control of the operator who, by manipulating the push button 21, may keep the headpiece at approximately the correct temperature to properly work the particular finishing material being used.

The illustrations of Figures 8 and 9 show two of the more common shapes of headpieces employed in the general run of furniture finishing. The unit of Figure 8 with its comparatively sharp rounded point 1I is designed for general work .but particularly the recessed surfaces of flutes, rosettes and the like while the comparatively fiat chisel point 12 of the unit of Figure 9 is adapted for general fiat work and finishing operations in entrant corners. Regardless of which one of several headpieces may be in use it is possible, as was explained in detail above, to very rapidly interchange the headpieces on the main body portion of the tool as the needs for particularly shaped headpieces arise.

I claim:

1. A surface finishing tool having a headpiece comprising a metallic shell havinga wall member provided with a flat ironing surface and having a recess therein of which said wall member forms a part, said recess being of longitudinal tapering form, an electric heater including a metallic sheath provided with extended iiexible portions and inserted in said recess whereby said extended fiexible portions will engage a tapered side of the recess so as to forcibly press the heater against said wall member, and a portion of said shell deformed to overlie a portion of said heater so as to preclude dislodgement of the latter from said recess.

2. In a surface finishing tool, a headpiece comprising a metallic shell having a wall member provided with a flat ironing surface and having a recess therein of which said wall member forms a part, said recess being of longitudina1 tapering form, an electric heater comprising a center sheet of insulating material carrying coils of resistance wire and provided in an end portion with a pair of keyhole-shaped notches, correspondinglyshaped terminal lugs connected with said coils and disposed in said keyhole-shaped notches whereby said terminal lugs are locked to said center sheet, cover sheets of insulating material overlying said center sheet and terminal lugs, a metallic sheath encircling said cover and center sheets and provided with extended iiexible portions, said heater being inserted in said shell recess whereby said extended flexible portions will engage a tapered side of the recess so as to forcibly press the heater against said Wall member, and a portion of said shell deformed to oVerlie a portion of said heater so as to preclude dislodgement of the latter from said recess.

WILLIAM C. JONES.

8 REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date D. 123,578 Shoenberg Nov. 19, 1940 1,442,648 Carter Jan. 16, 1923 1,478,319 Young Dec. 18, 1923 1,520,913 Simon Dec. 30, 1924 1,816,113 Feld July 28, 1931 1,938,630 Kuula Dec. 12, 1933 1,946,929 Chapatte Feb. 13, 1934 1,978,572 Earl Oct. 30, 1934

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