US2449839A - Balsa punch - Google Patents

Description

Sept, 21, 194s.

D. F BRITTLE BALSA PUNCH Filed Aug. 15, 1946 Patented Sept. 21, 1948 "UNTED N STATES PMeri-'rv 'on-1ct,"

a VBALSA Ponen Davia F. Bridle, weaverville, N; o. l Application August 13, 1946, serial No." 690,090

3 claims. (ol. 164-121) The present invention relates generally to tool andfmore particularly to a tool for punching holes `in brittle materials, such` as Vbalsa Wood "or the like.

One 'example of use for the present hole punch-- ing toolis in connection with the building of model airplanes. In making model airplanes from soft woods, such as balsa, a problem `arises when it becomes necessary to ypunch holes in the wood.` Model plane builders now usually laboriously cut holes by hand with a razor blade, making several cuts per holeto avoid splintering the wood In some instances punches have been attempted to be used, but because most of the holes required in balsa bulkheads and formers in model `airplanes are at the edge of the material, splintering action results from the `use of a punch, such as the known ticket-type.

It is the primary object of the present invention to provide a novel tool for punching holes, whereby the punch element is arranged to cooperate with a pair of members adapted to maintain the material being worked on in a level plane and compresse-d substantially at right angles to the punch during punching to avoid splintering.

Another object is to provide in a punch having a pairof cross-pivoted handles with jaw members continuing as an integral part thereof, a third a'ndlint-ermediate plate-like jaw with an opening for the punch element to work through for clamping and maintaining the material flat during the punching operation to avoid splintering.

A further object is to provide a novel punch which is economical to manufacture, rugged and eiicient in operation.

Other objects and advantages of the present invention will appear more fully from the following description when considered together with the accompanying drawing, wherein:

Figure 1 is a perspective view of the present invention.

Figure 2 is a side view of the device.

Figure 3 is a top view of the device.

Figure 4 is a longitudinal cross section view of the same.

Referring in detail to the drawing and rst with reference to Figure 4, the device comprises a pair of crossed handles IU and II having integrally formed jaw members I2 and I3. The handles are pivoted on a rivet I5.

The jaw member I2 comprises a flat T-head having an elongated plate I6 with a centrally disposed rectangular punch receiving opening Il therein; and the jaw I3 is a more conventional 2 l design and carries the punch element I9, whic is Ypreferably rectangular in cross-Section5 AIn forming the jaw I2 the same is made T-shaped, i. e.,*a relatively-narrow dat section 20, forms theleg of the T, seeFig.` 3f. The leg .Ztlt` continues from the mid-side edge of plate' IB.` This leg section 2l) has side anges 2I, which continue therefrom to merge into the handle II. InV the narrow flat leg section 2is an opening throughwhich extends the end of an elongated rivet-22. The rivet 22 is upset on the Vendz to limit the separatory movement-of the jaws Il2 and Ii3i and serves as a guide for these jaws and-a third intermediate fiat 'lf-shaped jaw 24liaving an elongated plate 25 similar in shape to fplate Isrcarried by jaw I2, as well as a flat leg section -with `an opening aligned with the opening in section 20 for rivet 212. The rivet 22 likewise serves'as a. mountfor a spring 26. This spring 26 is coiled around the rivet 22 between the punchljaw I3 and the thirdjaw 24, and tends to expand, so 'as to normally raise theijaw 24 above thepunch element I9 and `yieldingly urge it toward the jaw I2and its plate I6. i .s

The intermediate T-shaped jaw 24 has a centrally disposed rectangularlpunch receiving opening 28, -n Athevplate ,25, .in alignment` with a, similar opening I'I `inthe plate I6.` Each of the plates` I E `and 25has 'its length extending ftransverse the jaw` members, andthe jaw members .t2 and 24, as mentioned above, are guided by rivet 2-2 and urged toward each other by the spring 26. The leg 29 of jaw 24 continues from plate 25 and is curled around the shank of the rivet |45, which rivet is exposed through cut out portions of the handles back of the jaws I2 and I3.

In order to maintain the punch member I9 removed from the openings I1 and 2B in the plates I 6 and 25, there is mounted between the handles IU and II a wire spring 30. This spring comprises a piece of resilient spring wire of V- shape with a spring coil 3I at the apex thereof and a finger-loop 32 at the end of one leg of the V. The coil 3I serves to spread the handles apart and likewise the jaws I2 and I3, until the handles are squeezed together during the punching operation.

Operation The device is used by the operator grasping the handles and squeezing them together in the same manner as any other punch. However, the resulting movement of the parts is novel, for example, the plates I6 and 24 are placed over the material to be punched. Regardless of the thickvvmade of the same. this device, which may now occur to others skilled hess, assuming of course it is within the normal range of the jaw spread, the plates will yieldably apply some compressive stress on the material and keep it level and flat with respect to the punch member I9. As the handles ars squeezed this yieldable application of compressive stress is increased, until the punch nally penetrates the material, whereupon the squeeze on the handles is released and the spring 3l) returns the jaws to their respective normal posltiohs.

Thus have provided a novel hole puncher for materials likely to splinter, which gradually compresses the material and holds it level and" at with respect to the punch member after a reasonable degree of compression, until after the hole is punched, so as to prevent splinterliig of l the material. While I have specifically referred to using this device for punching holes in balsa wood for making model airplanes, it is. tubeV understood that many other uses may as well be Also other embodiments of in the art,I arev likewise intendedl to be covered hereby and reference should be had to the appended claims to determi-ne the scope ofV the present invention.

What I claim is:

-1. A` punch tooll comprising a pair of crosspivoted handles, a jaw carried by the forward extremity of one handle, a punch pin secured to .the jaw, a second jaw carriedby the forward extremity of the other handle, the second jaw being in the-form of a flat'plate having a width materially greater than the Widthof the handles and ofthe first jaw, anintermediate jaw of substantially the same width as the second jaw,

saidin-termediate jaw having `a relatively long tail piece extended rearwardly and pivotally connected with the. handles' to.y turn on` the pivotal center for the handles, the second and in:- termediate jaws having aligned openings to re ceive the punch pin, a rivet secured at onel end to the rst jaw at a point rearwardlyy from the punch pin, the secon-d2 and intermediate jaws having aligned: openings through which the rivet,

loosely extends, means upon the other end of the rivet for limiting the separatory movement yof the first and secondl jaws, and: a spring enfcircling the rivet and interposed between the rst jaw and the intermediate. jaw. i

2. A punch tool of the character described in claim 1, wherein the first mentioned aligned openings of the second and intermediate jaws are of polygonal outline and said punch pin is of polygonal cross sectional form to conform to the outline of the said openings of the second and intermediate jaws.

3. A punch tool comprising ya pair of handle members each having a forward end portion brnied 'tot provide spaced sides, the'rward end portion of one hanche being disposed-'between and in crossed relation with the sides of the forward end portion of the other handle, a pivot pin extending through the crossed portions of the handles, the forward extremity of the forehd portion of one handle having the sides `thereof bridged by an intermediate plate forming a relatively narrow jaw, a wide `jaw plate disposed across the forward extremity of the forward end portion of the other handle and having a rearwardly extending portion secured betweenuthe sides of the said other handle, a wide intermediate Jaw plate of substantially the same orxn as the rst wide jaw plate and in opposed relation therewith, said` intermediate jaw `plate having a central rearwardly extending tail portion termi-.- mating in an eye through which saidpivot, pin extends `'w-l-iereby the intermediate jaw plate swings on the pivot pin, said wide jaw plates havingv aligned openings, a punchr pincarried by the rst jaw and adapted to extend through `the aligned openings, a rivet secured at one endto the iirst jaw and extending through aligned openings of the wide jaw plates, means upon the other end of. the rivet for limiting theseparatory movement of the first jaw and the rstwide jaw plate, and an expansion spring encircling the rivet and interposed between the intermediate jaw plate and the first jaw. Y e t e DAVID BR'ITL.

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

UNITED STATES PATENTS Number Name Datel 451,180 Donovan Apr'. 28, 11891 472,793 Kuen U v e Apr. 12, k1892 712,482 Bernard 1 1 Nov. 4;.- 1902

Images