US2402478A - Machine for forming flat strips into articles - Google Patents

Description

June 13, 5346. WQQDBURN 2,4192473 MACHINE FOR FORMING FLAT STRIPS INTO ARTICLES FiledNov. 21, 1944 2 Sheets-Sheet l INVENTOR HA/POLO 6 WOODBU/PM June 11, 194. H, WOODBURN 4 ZAQZAT MACHINE FOR FORMING FLAT STRIPS INTO ARTICLES Filed Nov. 21, 1944 v 2 Sheets-Sheet 2 u' fiifl INVENTCQR HAROLD G Woooz/R/v,

Patented June 18, 1946 UNITED ES PATENT Il FFlCE MACHINE FOR. FORMING JFLAT, STRIPS ,INTO ARTICLES Harold 1G. Woodburn, vMunhall, Pa. Application November 21, 19,44,1Serialblo. 564,526

1. Claim. 1 This invention relates to machines for forming fiat's'tripsth'e'object b'eing'tolexpedite the formingof large'numbers of fla't strips so each is part- 'ly folded on "itself with "end portions bent inwardly "respecting the folding.

ample f the type of article is desired to producefrom the flatstrips. This thermocouple clip must be made from a flat strip of spring bronze to provide the necessary electrical conductivity with mechanical elasticity, the strip *being 'centra-lly folded parallelly on itself quite closely at I and thenloosely folded to provide straight flaring portions 2 with the ends of these latter portions right angularly bending-inwardly at 3 respecting :the foldings. The closely folded portion '1 *is providedwith registered-holes ltowhich an electrical conductor may be connected by means of a bolt and nut, 'andthe end portions 3 are provided with holes 5 which may be registered by springing together, or more closely folding, the straight portions 2 to bring the holes 5 into register, one of the thermocouple leads then being passed through this hole so that when the force required to spring the portions 2 together is released the resiliency exerted by the portions 2 urges the end portions 3 apart so as to jam the thermocouple lead tightly in the holes 5. Two of these c ips are required for each thermocouple and in a plant using a great number of thermocouples quite large numbers of these clips are required. Prior to the present invention they have been commonly formed individually by hand.

The machine illustrated by the drawings includes a fiat metal mounting plate 6 of sufiicient thickness to provide structural rigidity, this plate mounting a unitary die block 1 having a flat surface 8 contoured to flatly support the spring bronze strip S with the end portions, which are to be the end portions 3 of the clip, overhanging the flat surface 8 and free for bending. This unitary die block 1 provides another surface opposite the surface 8, this other surface having fiat portions 9 against which the strip S may be flatly positioned and being featured by hav-' 'ing a flat-sided recess 10 contoured for flatlysupporting partial-reception of the central portion of the strip S. Swinging levers 'lil "arepivotally'fixed .at l2 to the plate 6 so as to swing around the ends of thefiat surface8 of "the die block {these levers H moun'tingpunches l3for engagingthe overhanging ends of stripSwhen it is flatly supported by the surface "8 and bending'th'ese ends downwardly toprovide the'portions 3 of the clip; 'Stoppins T4 are mounted by the plate '6 in such 'a fashion that -when the 'two levers H are swung downwardly, which'm'ay'iae done manually with .the two levers swinging simultaneously, the punches l3 bend the overhanging ends of the strip S sufficiently far "so that, considering spring-back; the right angular end portions 3 are formed. Preferably the levers I! are provided with springs l5 which bias'the levers ll so that'the punches 13 are maintained at -inoperative positions excepting during operation of the levers ll.

This swinging action of the punches "provides for maximum simplicitybut' it creates theproblem of providing some sort of stop for engaging the ends of the strips as they are placed on'thesurface 8 andposition'in'g'them centrally of thisisurface with uniform amounts of overhang beyond its ends. Thi problem is solved by providing a retractable stop lfiim'oun'ted'for slidingrnovem'ent at right angles to the surface '8 "by -a guideway ll carried by the plate 6 in such a fashion that when the stop I6 is slid to a position beyond the level of the surface 8 it can be engaged by the ends of the strips as they are successively positioned on this surface to provide a means for positioning these strips centrally of this surface 8, and when slid oppositely away from the level of this surface 8 the stop is retracted so it is cleared by swinging of the punches I3 when the levers l l are operating. Furthermore, this action is automatically efiected by providing a means fOr efiecting retraction of the retractable stop Hi to a position providing this clearness for the punch l3 working at the end of the surface 8 where this stop It is, and with this means powered by movement of this swinging punch for simultaneous retraction upon swinging of this punch. This means takes the form of a link l8 that is pivoted to the lever I! and to the stop l6 so that as the lever swings to punch operating position it powers this stop it so as to caus its simultaneous retraction.

As so far described, provision is made for quickly placing the spring bronze strip on the surface 8, positioning it by the stop 16 so that the of the clip to their proper angularities.

strip is properly centralized on this fiat surface of the die block 1 and then by simultaneously swinging the levers H against the resiliency of the springs l5 quickly bending the right angular portions 3. Preferably the ends of the strips have already been punched to form the holes 5 prior to this described operation.

After each of the strips S has the end portions 3 formed it is next placed on the surface 9 of the same unitary die block 1 and is centralized there, such positioning requiring a stop similar to the stop l6 and this stop being preferably provided by forming the stop IS with an offset surface It properly positioned beyond the end of the surface 9 when the stop It is in its operative position, This means that the stop [6* retracts with the stop l6 automatically but this causes no inconvenience. The recess ID has a flared mouth It] and a punch I9 is provided having a flat tongue 20 which enters the fiat-sided recess l0 and effects folding centrally of the strip to provide the portion I of the clip desired, along with a flared fiat-sided portion 2| which works against the flared surfaces HJ of the recess ID to bend the portions 2 with the appropriate angularity respecting each other. This punch l9 must work linearly and is guided for reciprocation at right angles to the surfaces 9 parallel the surfaces of the recess ID by a guide 22 mounted on the plate 6, this punch I!) being powered by a lever 23 pivoted at 24 to the plate 6 and connecting with the punch 19 through a link 25.

The further operation is relatively obvious, the strips having the end Portions 3 of the clips formed as previously described are next successively positioned on the surfaces 9 by' the aid of the stop l 6 with the ends 3 pointing opposite the working direction of the punch IS, the lever 23 then being moved to force the punch I9 so its tongue 20 enters the recess ID, this forming the closely folded portion I of the clip, and so its surfaces 2l work the strip against the flared surfaces Ill of the recess It] so as to bend the portions 2 Thereafter the holes 4 are punched to assure accurate registration.

The advantages of the machine reside in its great simplicity and inexpensiveness, this being achieved by making the single unitary die block I perform the multiple operations required to produce the clips and by permitting the use of the simple swinging punches IS in conjunction with the stop required to properly position the strips on the die block surface providing strip support during operation of these punches l3. The Whole machine is very sturdy and permits the production of the many clips required around the average plant using thermocouples at a much greater rate than was ever achieved when these clips were made by hand, while at the same time producing the clips with more exact contours than was ever before possible.

To prevent undue buckling of the strip S while it is being worked on the surface 8 as described, transverse bars 26 are arranged closely over this surface near its ends and under which bars the strip may be slid when being placed on the surface 8.

I claim:

A machine for forming a flat strip so it is partly folded on itself with end portions bent inwardly respecting the folding, said machine including a unitary die block having a flat surface contoured to flatly support the strip with said end portions overhanging said fiat surface and free for bending and another surface having a fiat-sided recess contoured for flatly supporting partial reception of the central portion of the strip, in combination with punches arranged to bend said end portions simultaneously and another punch arranged to force the strip centrally into said recess, when the strip is successively positioned on said surfaces, whereby to provide for the multiple operations required by the use of a single unitary die block, at least one of the first named punches swinging around the end of said flat surface of said die so as to prevent the use of a fixed stop there for engaging the end of the strip and centering it on said flat surface, and a retractable stop being arranged there for so engaging said end and for retraction out of the way of said swinging punch, in combination with means for effecting said retraction and with said means powered by movement of said swinging punch for simultaneous retraction upon swinging of said swinging punch.

HAROLD G. WOODBURN.

Images