US2258843A - Blanking die - Google Patents

Description

Oct. 14, 1941-. A. H. BROWN 2,258,843

INVENT OR. ARTHUR H BROWN atentec ct. i4,

.NT OFFICE BLANKING .DIE

Arthur H. Brown, Denver, Colo. Application september 16, 1940, serial No. 356,911 `t claims. (c1. 164-119) rIhis invention relates to improvements in blanking dies and refers more particularly to a die for cutting openings of a predetermined size and shape in cardboard.

For diagnostic and operative purposes dentists find it essential to have X-ray pictures made of theirclients jaws and teeth to determine the shape of the roots and whetheror not there are abscesses or other faults present.

A dental X-ray mount consists of a sheet of suitable material, usually Celluloid or cardboard, with openings (windows) of different sizes and in suitable arrangement cut therein so constructed as to receive and retain dental X-ray negatives in proper relations.

Mounts of several designs (arrangement of windows in different combinations of sizes and arrangement as to horizontal and vertical disposition) are on the market but the number of designs would have to be almost infinite to meet the requirements of all cases. It is-necessary therefore, that a simple means be provided for quickly making mounts adaptable to any given case.

It is obvious that, in order to obtain satisfactory results from such mounts, the negative and the opening must be cut to predetermined sizes and to assure this the openings in the cardboard must be cut by means of blanking dies. Where large punch presses are employed the dies are of usual construction and present no particular diiculty.

Dentists who make their own X-ray pictures as well as those who specialize in this work and do it for others do not have powerful presses and f must therefore employ specially constructed blanking dies for making them which may be used with small hand operated presses.

It is the object of this invention to produce simple vand reliable blanking dies of such construction that the parts will positively remain in alignment during the entire life of the die.

Another object is to produce a blanking die comprising a base which is the female die and a resilient jaw having one end autogenously welded to one end of the base and to the underside of the free end of which the male die is rmly attached, thereby forming a unitary assembly which will positively retain its alignment.

It is also desirable in dies of this type that the cutting edges of the male and the female dies shall approach each other in substantial parallel alignment and Vfor this purpose the resilient jaw that carries the male die is made upwardly concave to compensate for the flexure to which it is subjected during operation.

The above and any other objects that may become apparent as this description prcoeeds are attained by means of a combination and an arrangement of parts that will now be described in detail and for this purpose reference will be 4had to `the accompanying drawing in which the invention has been illustrated, and in which:

Eigure V1 is atop plan View of the banking die;

Figure 2 is an Aend elevationthereof; y

Figure 3 is -a longitudinal section taken on line 3-,Figure1; and e e Figure 4; isa bottom plan View of the die.

In the drawing reference numeral 5 Vdesignates a base which is preferably made from Avtool steel and which, in the embodiment'sho'wn, is rectangular in shape. The shape of the base is, however, immaterial so far as the invention is concerned. K Y

Secured to the base is a jaw .6 which is made from eXible resilient metal such as spring steel, but may be made of any other suitable material. In the embodiment illustrated, the jawis provided with an end portion l of substantially the same width-as the base and which is offset from the jaw as shown in Figure 2'. The offset end is connected with the remainder of the jaw by means of an inclined portion 8. The oilisetr end` 'i is firmly attached or lwelded to the end ofthe base `as by spotwelding `or by electrowelding. From the upper end of the inclinedportion 8, `the jaw preferably tapers and terminates at 9` which, in the embodiment illustrated, is slightly spaced from the end of the base. The base is provided with an opening I0 which, in the embodiment illustrated, kis substantially rectangular and has rounded corners H and is provided on each side and end with two U or V-shaped notches l2. Secured to the under surface of the jaw is a male die I3V whose shape and size is substantially identical with the opening Ill. The male ydie is preferablyA made from tool steel so as to preserve its vcutting edge as long -as possible, but may be made from any other material that may be found preferable or more desirable for this purpose. The jaw 6 is biased away from the upper surface of the `base in the manner shown in Figure 2 and is spaced therefrom suciently to permit a card- -board I4 to b e inserted intoposition for being perforatedv by the die. The two` jaws of the die are moved towards each other by means of a suitable press which has not been shown, but the base of the press has been indicated by a broken line and designated by reference numeral I5, similarly the plunger or movable part of the press has been shown by broken lines and designated by reference numeral I6.

Assuming now that the parts are in the position shown in Figure 3 and that plunger I6 is moved downwardly, it will rst of all engage -the upper surface of jaw 6 and will then move the latter downwardly into engagement with the cardboard or other sheet' materialv I4 vwhich is to be blanked. 'I'he curvature of jaw 6 is such that due to the ilexure which takes place on account of its cantilever action, the inner surface of the male die becomes substantially parallel with the upper surface of the base when the male die contacts the upper surface of the cardboard. As the pressure increases the male die will continue its downward movement and shear the cardboard forming an opening therein of the exact shape and size desired. When the pressure is removed from the jaw, its resiliency will cause the male die to be withdrawn from the opening and the parts will then be in position to .repeat the operation.

In order to obtain the parallel position of the cutting edge of the male die to that of the female die, the jaw has been bent along the line I1 so that the part between the inclined wall 8 and line ll makes a slight angle with that part of the jaw that extends to the right of line IT. ,This angle has been designated by letter w in Figure 3. Since the jaw is of the cantilever type and autogenously joined to the base, it is evident that it will flex in response to the pressure exerted on it by plunger I6 and by making the jaw upwardly concave and proportioning the curvature to the flexure that results from the bending force applied to the jaw, the curvature and the flexure may be so proportioned that the male die will assume a position substantially parallel to the upper surface of the base as it comes into contact with the paper or other sheet material to be slieared. Although the parallel relationship just explained is desirable and is sought to be obtained, it is evident that a slight variation such as a few thousandths of an inch is not of material consequence and therefore the statement that the male die becomes parallel with the upper surface of the base must be considered within reasonable limits,

It will be observed that the jaw is made of sheet metal of considerable width and since the end 'I is welded to the base, the alignment will remain as originally constructed during the entire life of the die as the jaw cannot move sidewise without bending in the direction of its plane. Since the jaw is wide in proportion to its thickness, bending will not take place under ordinary conditions. It is doubtful whether suiicient force can be exerted on the jaw to bend it in the direction of its width without breaking the connection between it and the base. When the male die I3 is spot welded to the inner surface of the jaw, it cannot accidentally move relative thereto and the three parts once properly aligned will therefore retain their alignment during the life of the die, regardless of the amount of work accomplished by the latter.

I am aware that blanking dies of somewhat similar construction have been made in which the jaw and the base are connected by ordinary hinges oi by a curved spring strip. Such dies will not positively retain their alignment because the hinges will wear and only a slight wear will be Sufficient to displace the male die with respect to the opening and interfere with the successful operation. Where the two parts are joined by curved springs, as has been suggested, the jaw can readily be moved transversely and if submitted to sufficient pressure to give the spring a permanent set, the die will be ruined for further use.

The autogenous connection between the jaw and the base has been particularly pointed out for the reason that such a connection is of great importance in a die of this type as by this means positive alignment is assured. When the two parts are connected by screws or rivets, there is always a possibility of relative displacement as the interconnection between the fastening means and the base and jaw will nearly always permit of microscopic movements sufficient to interfere with the successful operation of the die. The offset of the jaw relative to the base is also of importance because by this means the male die member will more readily assume a position parallel with the supper surface of the base and provides space for the reception of the cardboard I4. The upward concavity of the jaw is also of importance in this combination for reasons already pointed out as by thus bending the jaw a proper degree, the parallel positioning of the two dies will automatically take place and as a result of this a more eiicient operation and a cleaner cut opening is obtained.

In the embodiment illustrated, the die is designed to cut opening in cardboard for the reception of X-ray films, but it is evident that the shape of the opening I0 can be varied from that shown in the drawing and the die illustrated can be used for many other purposes than the one pointed out as the primary purpose, and the shape of the die opening is therefore to be considered as illustrative only and not in any way as a limitation.

Dies constructed as above described can be readily substituted for each other in the press and positioned to make all the windows in alignment.

Having described the invention what is claimed as new is:

l. A blanking die comprising, a base having an opening forming a female die, a flexible resilL ient jaw member of substantially greater width than thickness having one end rigidly attached to one end of the base, the end attached to the base being offset to space the under side of the jaw from the base, the free end of the jaw having a male die secured to the under surface of the movable end thereof in position to cooperate with the female die in the base, that portion of the flexible jaw between the offset portion and the male die being upwardly concave, the curvature compensating for the flexure of the jaw in its movement towards the base whereby the two cutting edges of the dies will approach each other in substantially parallel relation.

2. A blanking die comprising, a base having an opening forming a female die, a flexible resilient jaw of substantially greater width than thickness having one end autogenously welded to the upper surface of the base, the under surface of the jaw being spaced from the upper surface of the base from its point of attachment thereto to its free end, a male die member immovably attached to the under surface of the free end of the jaw in position to enter the die opening in the base when the jaw is flexed toward the latter, that portion of the jaw between its point of attachment to the base and the adjacent edge of the male die being upwardly concave whereby the cutting edge of the male die will be upwardly inclined with respect to the upper surface of the base when the parts are in normal position and whereby the cutting edges of the dies will approach parallelism as the jaw is eXed in its movement towards the base.

ARTHUR H. BROWN.

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