Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.


  1. Advanced Patent Search
Publication numberUS2670527 A
Publication typeGrant
Publication dateMar 2, 1954
Filing dateFeb 3, 1951
Priority dateFeb 3, 1951
Publication numberUS 2670527 A, US 2670527A, US-A-2670527, US2670527 A, US2670527A
InventorsPerry R Roper
Original AssigneeAnthony Oberholtz
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Method for restoring deformed sheet metal surfaces
US 2670527 A
Abstract  available in
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)

March 2, 1954 P. R. RoPER 2,670,527

METHOD FOR RESTORNG DEFORMED SHEET METAL SURF' ACES Filed Feb. 5, 1951 wr www Yam Patented Mar. 2, 1954 METHOD FOR RESTORING DEFORMED SHEET METAL SURFACES Perry R. Roper, South Gate, Calif., assignor to Anthony Gberholtz, Los Angeles, Calif.

Application February 3, 1951, Serial No. 209,216

2 Claims.

This invention relates to improvements in metal working equipment and methods, and is especially concerned with the art of repairing and restoring original contours of metal forms such as relatively thin vehicle body sections, fenders, and similar parts which have become dented or otherwise damaged in collisions or the like.

Until development of the present invention repair processes and equipment for this purpose have been generally limited to certain well-known systems and tool combinations, such as those utilizing smooth weighted tough-faced steel dolly block elements of various straight and/or curved shapes adapted to be held under and in juxtaposition with the metal bodies being worked upon,

and conforming substantially to the original contour of such bodies, while co-operating hammer blows are struck against the outer or exposed dented surface of the damaged body at a location directly opposite the dolly-block so as to compress the dented portion of the damaged metal and force the same back as nearly as possible into original position, the usual finishing operations being thereafter employed, which may include the use of a pick-hammer (the striking head of which is in the form of an elongated narrow projection terminating in a rounded point of a size capable of working rather minute areas of damaged metal) which hammer is lightly applied from underneath the indented metal so as to bring any remaining minute depressed areas outward beyond the general periphery of the original contour in order that they may be led or ground down to bring about a satisfactory reforming of the outer surface of theV damaged metal by restoring a perfectly smooth surface before re-painting.

The repairman usually encounters considerable diiculty in attempting to re-shape the damaged metal by the above well known and generally used process while using the tool equipment of the prior art, because the body metal often becomes stretched and springy when dented and will not readily bend back into desired shape, and must therefore be carefully and painstakingly worked for along period of time with heat, hammer, and other equipment in order to avoid creasing, undue weakening, or perforation before any improvement becomes noticeable. Pounding the metal between a heavy flat steel hammer-head and the ordinary smooth weighted dolly-block in the usual fashion tends to further deform the metal by spreading, thinning, and warping and has the eiect of creating additional crown when the metal flexes outward toward the operator, making the same increasingly diiiicult to control. When a shrinkinghammer is used to localize and straighten the damaged metal against the anvil-like hard smooth backing-face of the ordinary dolly-block there is a tendency on the part of the struck area to crimp or buckle under the heavy force of the hammer blows, and it sometimes becomes perforate under such conditions, making progress all the more dicult.

In the use of pick-hammers the usual procedure is to alternately drive rather minute dented portions of metal upward or outward from the under side of the metal in the direction of the workman, and then lightly file the area of the dent on the workmans side of the metal, thus brightening the raised areas so that the portions still remaining somewhat depressed and out of line will be clearly revealed as contrastingly dark or dull among the file-brightened high spots. This process is continued progressively until the general contour is satisfactorily re-established, which latter condition will be revealed when the entire area worked upon ultimately becomes uniformly bright under action of the file or grinding device.

Since a pick-hammer has only a single working point, many light blows must be struck with it, usually upward or outward in the direction of the repairman, in a totally concealed location, against the damaged area, which requires much time 'to work a given relatively small area of metal in order to make the desired progress. Moreover, it is dicult to apply a pick-hammer properly against a particular point from underneath the damaged metal because of the usual lack of space in which to swing such a hammer between adjacently located and sometimes entirely concealed body parts, so sometimes it becomes preferable or necessary to effect total removal oi` the part damaged for purposes of more convenient repair,.whch, however, involves considerable disassembly time. The pick-hammers eicient manipulation requires considerable skill to be effective, While its careless or improper use could easily result in the metal becoming unduly and un-uniformly raised to a degree that extreme thinning and weakening, or possibly even perforation, might occur at the time of striking the pick-hammer blow or at the time of iiling the metal down if undue or uneven force is applied thereagainst. Under such conditions the addition of further metal by brazing or welding to reinforce the damaged area and to restore its proper contour and proportions prior to re-painting. must often be resorted to, adding substantially to the cost of the repair job.

It is the primary object of the present invention to provide new and novel tool equipment and repair methods which, when used in doing the repair jobs aforementioned, will greatly simplify the procedure, dispense to a very considerable degree, ifnot entirely, with certain tool manipulations heretofore requiring extremely expert services, and therefore enable a relatively inexperienced operator to perform the work involved satisfactorily and conveniently with :the aid :of but a minimum amount of easily handled equipment, and with a minimum amount of ztime and labor, at the same time generally overcoming the problems above referred to.

It is also an important object of the invention to provide a new and novel tool and repair system for the general purposes above set forth, which will enable the operator to dispense with theuse of a 'pick-hammer `in many instances, yet enable him -to perform the operations formerly requiring such pick-hammer just as expertly and in less time than was heretofore required.

A still-further object of the invention is to make possible the extended use of a relatively softfaced flat-head hammer in re-forming relatively thin 'sheet metal vareas Vin voperations where the vsame "could 'notheretofore be effectively employed because of the type of codoperating equipment available for 4such purposes.

Another 'and further 4important object of the invention lis kto provide a tool unit of novel design which, when'used in combination orco-operation with aconventionaltype'of hammerof given'size, creates a 'unique thin-metal repair Vsystem which is more eicient in operation and in results obtained than methods heretofore Vused for the same purpose, and incidental-ly extends toa very considerable degree the field of use of such conventional type hammer, so "that the use of a multiplicity -of hammers of different sizes as 'well as certain 'other equipment, can hereafter Vbe dispensed with in given operations.

A further object of the invention is to provide a new and novel form of easily handled Adollyblock used as a combined backing Vand forming element in repairing dentedfobiects made of relatively thin metal, which dolly-block shall be adapted to perform the same y'general backing function as Van old-'type dolly block 'while at the same *time 'possessing inherent properties rendering =it 'capable of simultaneously, conveniently, and efficiently performing additional functions heretofore requiring 'the use -of two or more separate tools which were extremely difficult to handle while ldoing the same class of work.

Another and still further object of the invention isto provide a `system of easily .manipulated labor-saving cio-operating tools utilizing a `new device of novel design for rie-forming dented metal, which system and equipment, insofar .as the action created and results obtained by use thereof, Vcombines :the Vworking principles, functions, 'and `advantages of, and now to va considerable extent replaces, lsuch old-type conventional equipment'as the pick-hammer, the smooth-faced dolly-block, the shrinking hammer, and certain other Adevices heretofore considered essential for performing certain repair operations, while at the same time 4also eliminating a lsubstantial portion of the overall weight of the tools Aand lequip-- ment involved, yet enabling the workman to produce equally expert results most economically and in a minimum of time.

Other and further objects of the invention will be apparent from the disclosures in the accompanying drawings and following specication.

The invention, in a preferred form, is illustrated in the drawings and hereinafter more fully described.

In the drawings:

Figure l is an elevation of ametal repair dolly 'for general use, 'made accordance with the `present invention.

Figure 2 is a sectional view of the same dolly taken on .the line 2 2 of Figure l.

Figure 3 is a View similar to Figure 1 showing the opposite side of the same dolly.

Figure 4is an end View of the same dolly showing ythe 'specially formed fender-ange contacting ,portion thereof.

Figure 5 is another end view of the same dolly showing the opposite end portion thereof.

Figure 6 is a pictorialwiew illustrating the prefer-red 'mannerof use tof the same dolly/during a fender-dent `repair operation, while employed in co-operation with a metal-working hammer taccording to the novel repair system of the invention.

Figure 7 vis :an enlargedfragmentary sectional view .showing in more detail Ythe novel metalworking :process depicted Vin Figure v6.

Figure 8 is a view rsinnlar .to Figure "7 illustrating the effect of a. blow :delivered by a yi'eldable face :hammer vupon the :fender-dent .area during a pre-finishing operation when the improved dolly element of this invention :is used as 4the backing element in :the process.

As shown .in ,the drawings:

V)Reference is .had tio Figures .1 to .5, `inclusive nf the drawings, illustrating :in detail :the unique and novel dolly-block ,-I 0 forming part of 'my invention, which kdolly-,block :is a :solid unitary lbody made of :any suitable metal providing the 4desired weight and atouglmess, with kone .-or more suitably contoured :metal 'working contact surfaces Il., J2, each .having many "contiguous tiny raised teeth or similar projections r1.3 uvhose .somewhat pointed iapices tare arranged substantially on a -fcommon plane according fo the .straight -or curved klines lcomprising :the dolly-.blocks 'special design `or contour, which `is .adapted to conform substantially to 4the .inner1 finden aor other fconcealed portions of Va relatively thin automobile fender Mor similar Vbody partrchichiit 'is adapted to :be held against during a repairfoperation.

The :narrow sides Iii, flf., fof ithe sdolly-block ,i0 are left relatively smooth 'and rare adapted pto be gripped between thengers of the workman, preferably inthe mannershownrin :Figure :6. 'Oneend of the dolly-block i0 may be formed with an "integra-l 'longitudinal extension il somewhat ,-narrower than the main :body portion of fthe dollyblock, one face of :said extension being :acontinuation .of the metal-working surface ft2., its -op posite side being Aarcuately or ctherwise cut out as shown :at i8, the said `extension :i 1 Abeing adapted Ato slidably .rest in the channel 1.9 created bythe normally in-turned edge 2l! of the metal job `element i4 being worked upon, whenever such 4in-turned edge is 4provided and whenever the damaged tarea is located near Fthe -edg-.e 2010i the'metal body i 4, the extremeend of the project ingfextension .IJ being also preferably contoured so `as to conform .substantially .to the shape `of the `in-.turned metallo, .so .that the workman can conveniently and with practically no .effort slide the dolly-block Ul along jthe surface o'f the 'body i4 while the block -is 4performing its backing function in coopera'tion with the hammer strokes 4aard-essi? being simultaneously struck against the opposite side of the 'job metal I4 by the operator in following the course of the dolly-block I as best shown in Figures 6 and '7. This feature also permits the workman to otherwise temporarily relieve himself of the blocks substantial weight while maintaining the tool I0 in position adjacent the work area between hammer strokes or during momentary rest periods, and the supported sliding motion permitted during operations enables the operator to more easily accomplish work along the edge in a more uniform fashion than heretofore. A

The edge portions of the dolly-block I0 are preferably rounded off somewhat to eliminate sharp edges so that the workman may be able to obtain a comfortable grip upon the device, the projections near the corners or edges being accordinglyV more or less flattened at such locationsso as to gradually taper downward toward and merge with the surface of the blocks sides I5, I6.

The teeth or projections I3 on surfaces II or I2 are knurls and their uniform arrangement forms said surfaces into knurled faces, the same being working faces of the block I0.

In performing a metal-straightening operation of the kind above referred to my dolly-block I0 is held against the dented area It in the same manner as vthe old type dolly-blocks, as best shown in Figures 6 and 7, and when used in co-operation with relatively light blows struck by the hammer 2| in the fashion indicated, will tend to prevent undue spreading and other objectionable deforming of the job metal I4 by reason of relatively uniform frictional or biting contact of the numerous projections I3 with the said job metal, simultaneously producing relatively uniform outwardly directed excrescences over a substantial area of the damaged surface to the extent desired and under a minimum of impact shock.

After the job metal I4 has been restored to substantially its normal initial condition, practically all stretch that may have been imparted thereto is absorbed in the mentioned excrescences (more particularly shown in Fig. 8). By filing, grinding or by other known methods, these excrescences are removed and the outer surface of the job metal rendered smooth.

My improved tool I0 is preferably used to back blows struck by a relatively large-faced hammer or mallet of the "soft or yieldable variety, such as those made of wood, iibre, rubber, or soft metal,

capable of providing the desired striking force.

By the use of such preferred hammer equipment it is possible to keep the shock of the impact at a minimum and at the same time provide a cooperating yieldable surface into which the raised metal points may become directed, as best shown in Figure 8, thus tending to prevent any forging or perforation thereof and preserving the original characteristics of the worked metal.

Thus the tool I0, by producing the same action as a plurality of simultaneous pick-hammer blows (each projection I3 functioning in the capacity of a separate pick-hammer), completely replaces the pick-hammer in this particular phase of the repair operation, while also re-contouring the body metal i4 in an obvious manner by reason of its appropriately designed general shape, which is adapted to conform substantially to the normal lines of the said body metal. Since the use of a pick-hammer is completely eliminated in most instances due to the substi 6 tution of my relatively thin toothed dolly-block, which is easily manipulated in cramped quarters, the complete removal of the damaged part under such conditions for convenience -in making repairs, is no longer necessary in most cases.

The use of my improved form of dolly-:block also permits the workman to deliver a normal but lmore effective hammer blow over the damaged area of the body metal with the unique result of properly re-forming the metal quickly and with much less effort than heretofore, ina manner tending to preserve the metals original form and characteristics `by materially reducing if not entirely eliminating the forging andvthin# ning action formerly inevitable when using the old methods and equipment. y

` Furthermore, my new system and equipment permits the use of a broader-faced hammer of any suitable or preferred diameter for most rapidly and effectively delivering the required force over a much larger portion of the damaged area than was practicable by use of the old methods and equipment, and with but a minimum number of blows, so as to make more rapid progress possible, since substantially the entire face area II or I2 is instantly responsive to the force of a single hammer blow, depending upon the dimensions of the striking face of the hammer used, all projections I3 within the radius of the hammer face being capable of simulta neously reacting to each hammer blow according to the amount of force applied and the shape of the damaged part relative to the tools referred to. Heretofore it has been considered necessary to use only small-headed hard-faced hammers for this particular type of repair operation against the backing action of the old type smooth-faced dolly block. Consequently the task was a tedious one, and slow and uncertain of results. The use of broad-faced hammers was deemed impracticable because of the well known tendency of the body metal to further deform, crimp, or buckle under the blows of the broadfaced instrument, which possibility is eliminated when my improved form of dolly-block is used.

By the use of my new and improved system the use of the referred to soft or yieldableface hammers, as well as the metal type broadfaced hammer, is very considerably extended to operations wherein they were not formerly considered adaptable or practical, and, as is perfectly obvious from the foregoing discussion, the number of tools required for performing a given job is thereby very materially reduced. Since the dolly-block element I0 simultaneously performs the functions of both pick-hammer and contouring device, only a co-operating hammer of suitable type is ordinarily required in combination with such dolly-block element for pursuing the work at the stage mentioned, eliminating much lost time formerly experienced by the workman when constantly picking up and laying down in alternate fashion the more numerous tools ordinarily used under the old repair methods.

Furthermore, since the numerous projections I3 of my dolly-block element automatically locate the so-called low spots or dents of the damaged metal Ill from the usually concealed location when held in position thereagainst in the general area of the dents as best shown in Figure 7, the formerly required special technique developed by the expert pick-hammer user under the old system of locating such low spots by means of alternate filing and pick-hammer blowsl .is lio-longer essentiel'L enabling; rthe most inexnerienced. workman to satisfactorily make the referred to repairs when usine my improved dolly-block according to the novel system herein disclosed, in a very minimum of time.

AISO, inasmuch asthe useof a. ling tool is greatly reduced if notrcompletely dispensed with by the provision of my speedy and eiective new metal working system above,` described, a very substan tia-l amount of working time saved on each i joh and the major cause of metal weakening during, repair is thereby removed, at. the same time also doing away with oneof the most laboriousunp1easant. andV met'a1-wastingv operations.

I am aware that many changes may be made and numerous details of construction varied throughout a wide range without departing from the principles of the invention.

I claim as my invention:

1..v A method for re-forming a deformed and stretched area of a thin metal member, said method consisting of restoring the deformed area to substantially its normal position while simultaneously with such restoration embodying the stretch in said area in amultiplicity ofA outwardly directed excrescences that are shallower than the thicknessr of the metal member, and then removing said excrescences. to. smoothen the outer surface of said member.

2.v A. method for restoring a deformed area of attain normally curved metal section that` con- Sists in progressively reducing the degree of deformation ofY said area by repeated hammering on the outer side: ofv the. deformed area. with; o tool substantially softer than the metal of the section while backing the innerA convex; Side oi the deformed area with a tool. harder than. the metal. of. the section to restore. the, deformed area to approximately its initial condition WhileV the harder tool forms the deformed area a multiplicity of outwardly directed indentations that are concave on the convex side of` the deforma.- tion and convexon the concave side, and thereafter removing the convex exoresoenoes of, said indentations to, thereby.r Smoothen the exposed normally curved surface of the rBStOred area.


References Cited. in the file of this patent UNITEDSFIATES PATENTS Number Name Date 1,196,942 Fraser Sept. 5, 191,6 2,065,461 Johnston v Dec. 22, 1 936 2,340,950 Ferguson Feb. 8', 1944 2,357,726 Carter Sept. 5, 1 944 2,416,916 Ferguson Mar. 4, 1947 2,986,857 Derby July 13, 1947 2,447,162 Conrad Aug'. 17', 1948 2,562,565 Merk July- 31, 1951 FOREIGN PATENTS Number Countryv Date 81,607 Switzerland Nov. 17, 1919 92,745 Switzerland' Jan. 17,- 1922

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US1196942 *Mar 23, 1915Sep 5, 1916William J FraserTool for straightening electrotype-plates and leveling the printing faces thereof.
US2065461 *Apr 16, 1934Dec 22, 1936American Sheet & Tin PlateMethod of removing cavities from sheet metal
US2086857 *Sep 9, 1935Jul 13, 1937Norman L DerbyMethod of making bimetallic elements
US2340950 *Mar 9, 1940Feb 8, 1944William H FergusonShrinking dolly block
US2357726 *Dec 7, 1942Sep 5, 1944Loyd Carter JamesFender tool
US2416916 *Apr 21, 1945Mar 4, 1947Porter Inc H KDolly
US2447162 *Apr 2, 1946Aug 17, 1948Conrad Harry EDolly block with serrated workengaging faces
US2562565 *Mar 28, 1947Jul 31, 1951Merk Albert WElectro-type straightener with rocking plate sections
CH81607A * Title not available
CH92745A * Title not available
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2788685 *May 26, 1954Apr 16, 1957Lockheed Aircraft CorpFlexible metal shrinking or expanding tool
US2799190 *Jul 27, 1953Jul 16, 1957Alfred E AwotApparatus for repairing dents in car bodies
US2974709 *Apr 8, 1955Mar 14, 1961Edgar Gretener A G DrProcess for the manufacture of embossed screens
US3036623 *Nov 16, 1959May 29, 1962Hanak AntonSteel forming dies
US3063236 *Jul 27, 1960Nov 13, 1962Cannon Chain Breaker Company LSaw chain rivet punch having pivoted jaws
US3131747 *Jun 6, 1960May 5, 1964Applied Power Ind IncClamp assemblage
US3133344 *Jun 11, 1962May 19, 1964Ben C KeaslerInternal knurling of bushing bosses
US3503245 *Oct 4, 1967Mar 31, 1970Brandl BenMethod and apparatus for removing defects from sheet metal
US4590783 *Jan 23, 1985May 27, 1986Nissan Motor Co., Ltd.Press forming process and apparatus therefor
US4661064 *Jan 30, 1985Apr 28, 1987North Bel S.P.A.Rotating tool for dentistry
U.S. Classification72/379.2, 29/DIG.230, 29/558, 72/56, 29/402.19, 72/705, 269/257
International ClassificationB21D1/06
Cooperative ClassificationB21D1/06, Y10S29/023, B21D1/065, Y10S72/705
European ClassificationB21D1/06B, B21D1/06