US2590024A

US2590024A - Method of making pinking scissors

Info

Publication number: US2590024A
Application number: US83895A
Authority: US
Inventors: Edgar M Lieberman
Original assignee: Individual
Current assignee: Individual
Priority date: 1949-03-28
Filing date: 1949-03-28
Publication date: 1952-03-18
Anticipated expiration: 1969-03-18

Description

March 18, 1952 E. M. I IEBERMAN 2,590,024

METHOD OF' MAKING PINKING SCISSORS Filed March 28, 1949 I 2 SHEETS-SHEET 1 will March 18,l 1952 E. M. LIEBERMAN METHOD OF' MAKING PINKING SCISSORS led March 28, 1949 2 SHEETS-SHEET 2 :fly-.1MM

. @@ZE 45K Gttornegs Patented Mar. 18, i952 UNITED STATES PATENT AOFFICIEL METHOD OF MAKING PINKING SCISSORS Edgar M. Lieberman, Jackson County, Mo.

Application March 28, 1949, Serial No. 83,895

(Cl. 'i6-104) 6 Claims. 1

This invention relates to a hand tool in the form of scissors or shears for making zig-zag cuts or pinked edges in cloth and like material, and more particularly to pinking scissors and the method of making same with blades having intertting, zigzag serrated or corrugated portions formed by stamping or pressing operation.

Conventional pinking scissors, -especially those used in dress making are heavy and expensive. They are usually made by accurately machining the serrated portions of the blade and then lappingh the blades in pairs to provide registration of the edges and clearance. Any misuse such as dropping or cutting heavy materials is apt to spring or otherwise alter the required perfect Working relation of the blades. Such misuse destroys the usefulness of the scissors and restoration of same can only be accomplished by sending them to the factory for realignment, relapping or replacement.

The objects of the present invention are to provide a pinking scissors construction that is simple, relatively inexpensive, efficient in action, and when dull or sprung by misuse may be sharpened and restored to usefulness by the employment of no better skill and equipment than that possessed by an ordinary scissors grinder; to provide relatively light weight pinking scissors having blades formed from sheet or strip steel and having interfitting zig-zag shearing portions forming opposed cutting edges of desired shape; to provide pinking scissors having intertting corrugations stamped or pressed into the shearing portion of the blades to form opposed cutting edges which cut on a Zig-zag line, said corrugations being spaced from the back edge of the blade so that a reinforcing rib structure is formed eliminating change in the pitch of said corrugations when stressed as by cutting heavy material and at the time of heat treatment; to provide pinking scissors with blades of metal having slight resiliency and shaped to' have desired relative hook, twist and ride in the blades; to provide a method and sequence of steps therein for making pinking scissors blades of desired shape and contour by stamping or pressing operations; to provide a method of forming pinking scissors blades in pairs by stamping the blades together in overlapped relation to form interfitting serrations or corrugations therein the overlapping surfaces of the blades being identical; to provide scissors having sharp points so that material can be pierced before being cut; and to provide a method of making pinking scissors Quickly and eiiiciently in mass production.

In accomplishing these and other objects of the present invention, I have provided improved details of structure and sequences of method steps illustrated in the accompanying drawings wherein:

Fig. l is a side elevation of a pair of pinking scissors.

Fig. 2 is a plan view of the pinking scissors taken at right angles to Fig. 1.

Fig. 3 is an enlarged longitudinal sectional view through the blades and pivot therefor.

Fig. 4 is a transverse sectional view through the blades on the line 4 4, Fig. 2, the cutting edges being in shearing position.

Fig. 5 is a transverse sectional view similar to Fig. 4. and showing the blades moved to Aclosed position.

Fig. 6 vis a plan View of the bottom die member used ifor forming the vpinking scissors blades.

Fig. 7 is a longitudinal sectional view through the bottom die member on the line '1 -l, Fig.- 6, illustrating a pair of bladeblanks in position 4prior to forming.

Fig. 8 is a ylongitudinal sectional view through the die block illustrating the position of the scissors blades Aafter forming and punching operations.

Fig. 9 is a transverse sectional view through the bottom ydie block and blanks `on the line 9 9, Fig. 7.

Fig. 10 is a transverse sectional View through the die blocks on the line ID-I Il, Fig. 8.

Referring more in detail to the drawing:

I designates a pair of pinking scissors constructed inaccordance with the present invention and comprising

complemental blade members

2 and 3 provided with handle or gripping portions f5 and 5 respectively. The blade members have intermediate hub portions 6 and 'I pivotally connected together as at 8 vto operate about an axis 9.

The hub portions 6 and 'I are preferably formed in the blades and consist of flat circular plate Vportions Ill and II having peripheral cylindrical walls I2 and I3 respectively. The walls I2 and I3 are coaxial and of such relative size that the inner surface I4 of the wall I3 rotatably vengages the outer surface I5 of the -wall I2 and operates vas a bearing for the blades. The plate portions are spaced apart by a suitable washer I8 engaging the adjacent faces I 'I and I8 of the plate portions I0 and I I respectivelyrsaid blades being connected by means of a suitable bolt or the like I9 having a head 2B engaging the outer face of the plate portion I'I and a polygonal shaped shank 2| extending through corresponding

shaped apertures

22 and 23 in the plate portion II and washer I6. The shank 2| terminates in a cylindrical portion 24 extending through an aperture 25 in the plate portion IU to rotatably mount the plate portion thereon. The end of the cylindrical portion 24 of the shank is threaded for reception of a nut 25 engaging the outer face 2l of the plate portion I0 to retain the hubs in assembled operative position. The washer i E may have parallel side faces orbe suitably beveled to impart desired ride tothe blades.

Integral with and extending rearwardly from the hub portions are extensions 28 and '29 on the

blades

2 and 3 respectively, said extensions preferably being of reduced width and of suitable shape and length to mount the handles 4 and 5 respectively. The handles 4 and 5 may be formed of metal, plastic or other suitable material, molded or otherwise suitably secured to the

extensions

23 and 29 to provide a strong, attractive shape and structure of the handle portions. The handles are preferably formed to t the hand of the user for maximum comfort and can be offset to one side of the line along which the closed blades extend. Obviously the portion of the extensions between the handles and the hubs may have complemental bends to provide the desired offsets of the handles.

The

blades

2 and 3 are integral with the hub portions and extend outwardly therefrom substantially opposite to the extensions 28 and 29.l

Each of the

blades

2 and 3 has back edges 30 preferably tangential with the outer periphery of the wall i3 of the hub portion 'l and converging toward the longitudinal'axis 3| of the blades at the free ends 32, said back edges preferably terminating in curved portions 33 at the free ends to provide sharp points at the ends 32 and to enhance the appearance of the scissors. The opposite or inner edges 34 of the blades have flat ground faces 35 spaced inwardly from the longitudinal axes of the respective blades as illustrated in Fig. 1 to provide an overlap of the blades when the blades are in closed position, the inner edges 34 of said blades sloping relative to said longitudinal axes to provide greater overlap and width of the blades adjacent the hub portion.

Formed in the blades and arranged substantially transversely of the respective axes 3i are a plurality of corrugations 36 which extend from the inner edges 34 toward the back edges of the blades, said corrugations terminating as at 3l in spaced relation to the back edges 30 to form a rib 38 adjacent said back edges. In the preferred form the pitch or spacing of the corrugations is equal throughout the length of the blades, said corrugations being concentric with the axis 9 of rotation of the blades. The corrugations formed in the blades are so arranged that the overlapping surfaces are identical, the inner surfaces 39 of the blades having matching depressions 49 and elevations 4I, thus assuring a perfect fit of the surfaces of said blades into one another. While the corrugations may be of any desired shape, they are preferably formed by stamping or pressing same into the blades whereby oppositely inclined inner faces of each of said corrugations are straight in cross section and terminate in small complementary arcs along the crest 42 and root 43 thereof as shown in Fig. 3. It is preferable that the corrugations be so formed that the lateral crests of adjacent corrugations are uniform or equally spaced relative to the plane of the ribs 33 on the blades.

The

blades

2 and 3 are twisted or otherwise formed whereby the planes normal to the inner surfaces of the blades intersect the planes defined by the axes 9 and 3l as shown in Fig. 4, however the normal planes of the respective blades are substantially parallel with the blades in closed position and the angle of said normal plane with the plane defined by the

axes

9 and 3| is such that the cutting-edges 44 on the respective flat faces 35 engage as shown in Fig. 4 to provide a shearing action on material therebetween, and as said blades are moved to closed position said angle provides clearance between the respective complementary surfaces of said blades as shown -in Fig. 5. The material from which the blades are formed has slight resiliency and said blades are bent to provide what may be termed a hook herein, and the resiliency of said blades tends to force the complementary inner edges thereof together. With this arrangement, when the blades are open as in Fig. l, intersecting cutting edges of the blades will be in engagement and the free ends will be substantially one over the other and as the blades are moved to closed position the free ends will be in engagement and the portion adjacent the hubs will be spaced as shown in Fig. 3, thereby maintaining engagement of the cutting edges at the point of cut throughout the length of the blades due to the spacing washer I6, the hook, twist and resiliency of the blades. This action or ride of the blades may be changed by using a beveled washer I6 between the hub portions of the blades.

In cutting material, any tendency of the corrugations to be deformed or to change the registration of the corrugations is resisted by the ribs 38. As the scissors are closed, each opposed pair of cutting edges of a cooperating pair of corrugations rst meet at the root of one corrugation and close toward its crest diagonally of the general direction in which the shears are pointing and then along the opposite side of the corrugations from the crest diagonally in the opposite direction to the root, thus forming one undulation of the Zia-zag cut. -If the blades become sprung or the hook or ride is otherwise reduced, they can be bent easily to increase the hook and the pressure at the intersecting cutting edges. Also when said cutting edges become dull, they can be sharpened by grinding the hat faces 35 as in grinding ordinary scissors.

In making scissors of the type illustrated and described,

blanks

45 and 46 are stamped or otherwise suitably cut from sheets or strips of steel having suitable thickness, hardness and other physical characteristics, said blanks being of suitable size and shape to make the

blades

2 and 3, the hub portions 6 and 1, and the

handle extensions

28 and 29 respectively. The

blanks

45 and 46 are placed in overlapping relation as shown in Figs. 7 and 9 and arranged in the cavity 4l of a lower die member 48, the cavity 41 being such as to Asubstantially conform to the outer surfaces of the blade 3 as later described. An upper die member 49 having projections 53 cooperating and substantially corresponding shaped to the cavity 4l and substantially to the outer surface of the blade 2 is moved downwardly to press or stamp the

blanks

45 and 46 into a ,shape corresponding *to the space between the respective portions of the cavity -41 and projections 53 when the die members are in closed position as illustrated in Figs. 8 and 10. This operation forms the blades so that the overlapping inner surfaces are identical. VJhile the die

members

43 and 43 are in closed position with the blade members therebetween or said blade members are in other suitable fixtures, a punch 5I is moved through suitable die apertures v52 and 53 to punch holes 54 in the hub portions and coaxial with the axis 9. The die members are then separated and the formed blanks removed for nishing operations as later described.

In forming the particular scissors illustrated in Fig. 1, the cavity 4l in the lower die member 48 preferably is provided with a cylindrical recess 55 conforming substantially in shape and size to the outer surface of the hub portions l. In theV particular die cavity illustrated the blank 46 for the blades 3 is onthe bottom, therefore a cavity 56 corresponding in size and shape to the extension 2S is provided in the block 63 and is cut deeper into the blocks by the thickness of the metal of the blanks than the cavity 5i corresponding in size and shape to the extension 28. The relative angular disposition of the cavities 56 and 5l is such that said extension cavities are substantially in the relative position as the handle extensions would assume when the shears are in closed position, that is the longitudinal axes 3i thereof overlie each other.

Extending from the hub cavity and in the direction opposite to the handle extension cavities 55 and 5l is a cavity 58, the side edges 59 and 6G of which are preferably tangential to the larger diameter of the hub cavity 55, said side edges corresponding in shape to the back edges 3i! of the

blades

2 and 3 respectively. The edges 59 and SS extend downwardly into the block t3 and terminate in shoulders 5i and 62 of different depths from the face t3 of the die block i3 to provide the desired twist in the blades relative to the axis 9. The width of the shoulders iii and d2 is substantially the same as the width of the ribs 33 of the blade members, said inner extremities of the shoulders terminating in undercut portions 6d extending downwardly into the block 43 below the lowermost part of the forming portion oi the cavity F58. Extending upwardly from the undercut portion ed and having uniform spacing @5 from the inner edges of the shoulders 6l and B2 are corrugation form ing portions 5E of the blocks, the spacing E?) being such as to permit forming the corrugations and the ribs in the blades without fracture or the metal thereof. The corrugation forming portions preferably consist of alternate projections and depressions El' and @8 respectively of substantially triangular cross section, said projec tions and depressions being arcuate transversely of the cavities and concentric with the axis of the hub portions, the pitch, sise and shape of the projections and depressions being such as to form the outer Lirface of the corrugations on the blade member 2.

The inner edges of the blanks i5 and iii preierably coincide with the side edges GS and it respectively of the corrugation forming portions 66 on the die. The upper die member i9 has downwardly projecting male members li 'Fil having outer edges adapted to substantially engage the side edges 5@ and 6B of the cavity 58, said members "ii and 'i2 being substantially the same width as the shoulders 6i and t2 and of such depth relative to the face i3 of the block lli) as to engage and press a single thickness of the metal of the blank between the 'lower faces of said members 'H and 'i2 and the shoulders 6l and 62 respectively, when the die members iS and i9 are in closed position. The upper die member 49 is provided with undercut yportions lil aligning with the undercut portion of the member Q8. The die member also has matching projections and depressions 'l5 and TES respectively corresponding in size, shape and pitch with the projections and depressions of the member t8, the projections l5 aligning with the depressions 63 and the depressions 'i6 aligning with the projections 67. The upper die member is also pron vided with a cylindrical projection il aligning with the recess 55 and with projecting portions 'I8 adapted to enter the cavities 56 and 5i. The relative spacing and arrangement of the cooperating projections and depressions the respective dies are such that when the dies are closed all) the projections and depressions will close on the metal of the blades, a single thickness of metal being between the projections and depressions at the handle extension portions and at the ribs of the blades and two thicknesses of metal being between the hub portions andthe corrugation forming portions for the blades.

The projections 61 and 'l and the

depressions

53 and 76 are preferably arranged on a slope relative to the faces of the rdies to provide the desired twist in the blades. The blanks 45 and it are placed in the cavity 41 and the die members closed. Suitable pressure is applied thereto to form the metal as shown, the design preferably being such that there is a controlled spring back when the dies are opened. By pressing the blade members between the dies as described, the contacting surfaces of the hubs and the inner surfaces of the respective corrugations formed on the blades are complementary and the pivotal relation of the blades and the concentric arrangement of the corrugations is assured. The apertures 5ft are preferably punched while the blades are held as described.

The formed blades are removed from the dies and the apertures in said blades shaped to conform to the shape and size of the portions of the screw Shanks on which they fit. The inner edges of the blades are ground to remove interfering portions of the blades and to sharpen the cut'- ting edges thereof. rJhe grinding of the edges also reduces the spacing of the inner edges of vthe iinished blades from the longitudinal axes thereof to provide the desired angle of approach of the cutting edges to the material.

The 'blades may be heat-treated if desired to provide suitable Aphysical characteristics vand ythe handles i and 5 molded or otherwise suitably applied to the extensions thereof. The inner faces of the blades are then given a final grinding for sharpening same. The blades are placed with the apertures therein in alignment and with the washer le spacing the hub portions thereof. The shank of the bolt is inserted through the apertures and the nut applied and tightened to secure the blades in operative relation. The fact that the hubs, corrugations and apertures are formed in a die, the forming members of which are concentric, obviates the possibility of the blades being eccentric. r'his fact assures registering of the projections and depressions of the blades and shearing thereby.

It is believed that I have provided vpinking scissors of light, durable structure and eiicient action, and a method of making such pinking scissors by stamping and particularly by stamping said blades in overlapping relation 'to' form corrugations or teeth thereon and control the spring back whereby the inner surfaces of the blades are complementary, which together with the particular arrangement of `the blades and he forming of the twist, hook and ride thereof provide a positive shearing action with sufficient clearance and yet have scissors that can be sharpened by a simple grinding of the inner faces of the blades.

What I claim and desire to secure by Letters Patent is:

l.. The method of making pini/:ing scissors which comprises, cutting a pair of fiat metal blade blanks, placing said blanks one on the other with the edges of one parallel and offset transversely of the blades from the edges -of the other, forming mating portions of the blades the axes of which are coincident and become the ultimate pivotal axis of the scissors, forming a plurality of corrugations in the overlapped portions only of the blades concentric with the ultimate pivotalaxis of said blades, the adjacent faces of the blades being complementary, bending the blades to incline 'same to a plane normal to the ultimate pivotal axis thereof, removing a portion along the length of each of the overlapped edges to form cutting edges on said blades, and pivotally connecting together' the formed blades for movement about the ultimate axis.

2. The method of making pinking scissors which comprises, cutting a pair of flat metal blade blanks, placing said blanks one on the other with the edges of one parallel and offset transversely ofthe blades from the edges of the other, forming mating portions of the blades the axes of which are coincident and become the ultimate pivotal axis of the scissors, forming a plurality of corrugations in the overlapped portions only of the blades concentric with the ultimate pivotal axis of said blades, the adjacent faces of the blades being complementary, bending the blades to incline the longitudinal axes thereof to the ultimate pivotal axis, said longitudinal axes crossing toward the free ends of the blades, ree

moving a portion along the length of each of the overlapped edges to form cutting edges on Vsaid blades, and pivotally connecting together the formed blades for movement in substantially parallel planes about the ultimate axis.

3. The method of making pinking scissors which comprises, cutting a pair of ilat metal blade blanks, placing said blanks one on lthe other with the edges of one parallel and onset transversely of the blades from the edges of the other, forming mating portions of the blades the axes of which are coincident and become the ultimate pivotal axis of the scissors and simultaneously forming a plurality of corrugations in the overlapped portions only of the blades concentric with the ultimate pivotal axis of said blades, the adjacent faces of the blades being complementary, bending the blades to incline same to a plane normal to the ultimate pivotal axis thereof, bending the blades to incline the longitudinal axes thereof to the ultimate pivotal axis, said longitudinal axes crossing toward the free ends of the blades, removing a portion along the length of each of the overlapped edges to form a cutting edge on said blades, and pivotally connecting together the formed blades for movement in substantially parallel planes about the ultimate axis.

4. The method of making pinking scissors which comprises, cutting a pair of flat metal blade blanks, arranging the blanks one on the other With the edges of one parallel to and offset transversely of the blades from the edges of the other, forming cylindical interi'ltting members in the blades the axes of which are coincident and become the ultimate pivot axis of the scissors, said cylindrical members having adjacent faces in planes substantially normal to said pivot axis, simultaneously forming a plurality of equally pitched corrugations in the overlapped portions length of each of the overlapped edges to form cutting edges on said blades, and pivotally connecting together the formed blades for movement of the blades in substantially parallel planes about the ultimate axis, whereby the cutting edges of the blades are in engagement at their point of intersection and overlapped portions of said blades are in spaced relation.

5. The method of making pinking scissors which comprises, cutting a pair of flat metal blade blanks, arranging the blanksl one on the other with the edges of one parallel to and offset transversely of the blades from the edges of the other, forming cylindrical intertting members in the blanks the axes, of which are coincident and become the ultimate pivot axis of the scissors, said cylindrical members having adjacent faces in plan-es substantially normal to said pivot axis, simultaneouslyT forming a plurality of equally pitched corrugations in the overlapped porti-ons only of the blades from the cylindrical members to the free ends of said blades, said corrugations being concentric with the ultimate pivot axis of said blades and having crests of adjacent corrugations on opposite sides and substantially equally spaced from the plane of the blade blanks, the adjacent faces of the blades being complementary, bending the blades to ncline same to a plane normal to the ultimate pivot axis thereof, bending the blades to incline the longitudinal axes thereof to the ultimate pivot axis, said longitudinal axes crossing toward the free ends of the blades, removing a portion along the length of each of the overlapped edges to form cutting edges on said blades, and pivotally `connecting together the formed blades with the adjacent faces of the cylindrical intertting members in aligned spaced relation for movement of the blades in substantially parallel planes about the ultimate axis, whereby the cutting edges of the blades are in engagement at their points of intersection and overlapped portions cf said blades are in spaced relation.

6. The method of making pinking scissors which comprises, shaping a pair of incompletely formed metal blades, placing one of said incompletely formed blades on the other in partially overlapped position with the edges of one offset transversely from the edges of the other, forming mating portions of the blades the axes of which are coincident and become the ultimate pivotal ,axis of the scissors, and simultaneously pressing a plurality of corrugations in the overlapping portions only of the blades whereby the adjacent faces of said blades are complementary, said corrugations being concentric with the ultimate pivotal axis of said blades.

EDGAR M. LIEBERMAN.

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

UNITED STATES PATENTS Number Name Date 397,692 Clarke Feb. 12, 1889 491,078 Clarke Feb. 7, 1893 609,564 Olmsted Aug. 16, 1898 2,268,626 Sigoda Jan. 6, 1942 2,284,664 Kissling June 2, 1942 2,387,053 Brown Oct. 16, 1945 2,395,896 Mitchell Mar. 5, 1946