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Publication numberUS1748638 A
Publication typeGrant
Publication dateFeb 25, 1930
Filing dateFeb 24, 1927
Priority dateFeb 24, 1927
Publication numberUS 1748638 A, US 1748638A, US-A-1748638, US1748638 A, US1748638A
InventorsCrum Harvey E
Original AssigneeCrum Harvey E
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Electrician's safety knife
US 1748638 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

Feb.- 25, 1930. H. E. CRUM 1,748,638

ELECTRICIAN'S SAFETY KNIFE Filed Feb. 24, 1927 va i ls", Z7

Patented Feb, 25, 1930 i P-Arev EtnoTRIcIAns sarn'rv KNIFE Application file d February 24,1927. Serial No. 170,669.

This invention: relates to" knives and more I particularly to that class of knives which are'adapted for use by electricians and the like for peeling and cleaning insulated elec' ,jstrical conductors'k A object 'ot y invention is to provid an improvement upon the disclosure illus trat edin' myco-pencling application, Serial No. '157,697' filed December 29,'l926..

:Another object of this invention .'.is to'pros" vide" aknifein' which the metallic; blade is completely insulated from thehandle, so that the same may be use'dupon a wire which is charged without danger of transmitting electricalenergy fr'omthe wire to the human YA further object of this invention is to ripping the clothin'grof the user or endanger- Y material which will act as an electric'insu' provide' a knife wherein the. actual cutting v f blade is slidable within the handle an'd'the ""2 same when not in use may be withdrawn into the handle, thereby preventing theknife from ingleatherin the tool-boXQ v A still further object of this'inv'e'ntionls to provide a knife which'may be' 'hungrupon I theelectricians belt when the blade: is concealed withinthe handle and "which may be vo uickly'removed from the belt and the knife blade exposed foruse.

' Yet, a still further object of'this invention Y is to [provide an-electricianlslsafety knife vet-out of order and which will. withstand wherein meansare'provided on 'the'same for v holding the knife either in retracted-or extendedposition.

A still further objectof this invention is to provide an electricians "knife which is "exftremely' durable, which is veryunlikely to ith the foregoing and other objects in view which will be made manifest in the following detailed description and specificallyv :pointed out in the appended claims, refer? ence is had to the accompanying drawings tion; wherein:

for an illustrative embodiment of the invenjian-Figure l-"is a sideelevation of my knife showing blade'exposed and lreadyvfor Juse. I n j I j @j j t k p Fig? 2' 'is a sectional view takenv substanman along the lin 2' of u in the direction of the arro i V Fig. 3 is a view in sid e elevation of a part forming the locking device in the improved Fig. 4: is a top plan view. of thesame."

knife-consists of a handle made'npottWO complementary parts andll which present arounded exterior surface having reduced ends which receive surrounding bands 12 and 13holding the two partslO an'dll togethen-- The two parts lO and 11 which form the'handle are formed of thoroughly seasoned-"wood, pressed fiber or equivalent- 'a blade '16 is 'slidable," The knifeblade 16' is providedwith' a cutting edge 17and a scraping'edge' 18 on one end andan aperture 19 on the opposite end. This blade issomeof the'tact that it is 'slid'able in the sl'ot,' it

"may have either end dispose'd'wholly within the handle or projecting-therefrom.

-.Figures 1 and 2- illustrate the. knife blade havingthe end provided with the-cutting edge projecting from the handle andthe end having the aperture 19' disposed wholly 'Wlth- :init; By shifting the blade within the. slot what longer than the handle, and byvirtue j the end havingthe cutting edge can be caused" to assume a position wholly Within the handle,

andthe end having the aperture l9 projecting from 'thefopposite end of thehandle, The

lower part 11 of thefhandle has the groove formed thereonideepened intermediate its 'endsas indicated at 20 and 21, to receive the ends of a bowed spring 22- Near the center of the part 11 the groove 15 isdeepened materially as indicatedat 23', int OWhiQh the cen ter of the spring 22 is capable of being depressed. The other part of the handle indicated at 10 has a circular aperture 24 formed therein which is reduced in diameter near the exterior of the handle to form a shoulder 25 which serves as an abutment adapted to be engaged by a flange 26 on a button 27 which fits within the aperture 24. This button is also formed of insulating material and has its top accessible from the exterior of the handle. On the spring 22 at approximately its center, there is fastened a part U-shaped in cross section having a base or foot 28 fastened directly against the top of the spring 22. An up-. standing portion 29 extends upwardly from the base 28 at the side edge of the spring and is then bent forwardly as indicated at 30 to provide a portion fitting in a recess on the under side of the button 27.- A pair of notches 31 and 32 are formed in one edge of the knife blade 16, which notches are capable of receiving the base or foot 28. On the op posite side of the knife blade there is formed a long notchr33 into whichextends theend I of a screw '34 which is preferably formed of insulating material so that the screw, by en gaging the ends of the notch 33, limits the sliding movement of the blade within the handle. The ends of the spring 22 are provided with wings which are bent upwardly indicated at 35 and toward each other as indicated at 36, to provide loops in the ends of the spring through which the blade slidably extends.

The operationof the improved knife blade is 'as follows:

l/Vhen it is desired to use the cutting edge 17 or the scraping edge 18, the button 27 is pushed downwardly. By reasonof its engagement with the portion 30 of the part fastened to the spring 22, it will move the spring downwardly into the recessj 23 and cause the base or foot 28to passout of-the' notch 31. When thisis done, the knife blade is free to slide within the handle, and that end having the aperture 19, can be pushed, causing the edged end of the blade to be exposed. On release of the button 2?, the spring will urge the button outwardly and carry the base or foot 28 into thernot-ch 32, the base or foot thus serving as a lock locking the blade in this position. When it'is desired to discontinue using the knife, the button 27 can be depressed, causing the base 28 to move out of the notch 32 and the blade can be caused to slide backwardly, and on release of the button the base 28 willagain enter the notch 31 In this position the edged end of the knife blade is disposed entirely within the handle and the apertured end is projecting therefrom, permitting the knife to besuspended upon an electricians belt by passing a snap hook or equivalent part on the belt through the aperture 19. The loops provided on the, ends of the spring 22 provide good bearing surfaces for the ends of theknife blade so that the edges of the knife blade will not cut into the wood or other material forming the handle.

From the above described construction it will'be appreciated that an improved electricians knife is provided, wherein there is a slotted handle formed of insulating material in which a blade is slidable, and that either end of the blade is capable of assuming a position within the handle with the other end projecting therefrom Also, when in either of its extreme positions, the knife blade is lockedin that position and can not be moved from that position until the button 27 has been depressed sufficiently to move the base 28 out of its notchin the knife blade. This construction prevents an electrician from becoming accidentally cut by the cutting edge 17. and also prevents his becoming injured by the edged end of the blade coming in contact with a charged wire while the knife is suspended from the electricians belt. It will be noted that all portions on the exterior surface of. the handle are electrically insulated from the blade so that the knife can be used for cutting insulation and scraping a charged wire without danger to the person using it.

It will be understood that various changes in the details of construction may be made without departing from the'spirit or scope of the invention as defined by the appended claims. V

I claim:

1. A knife comprising a slotted handle formed of insulating material, a blade slidably disposed within the slot within the handle, said blade being longer than the handle and being capable of being moved into a posit-ion wherein one end; is disposed within the handle adjacent is respective end thereof, and the other is'projecting therefrom or into another position wherein the first mentioned end is projecting from the handle and" the other end is disposed therein adjacent its respective end, a resilient strip disposed within the handle, said strip' carrying means adapted to enter notchesin the blade and urged into such position by the resilient strip to lock the blade in either position,'-and means for depressing the resilientstrip causing said means to permit the blade to slide in the handle, said resilient strip providing loops at its ends through which the blade slidably extends, v

2. An electricians knife comprising a slotted handle, a blade slidably disposed within the slot'inthehandle, resilient means disposed within' the handle, adapted-to enter notches in the blade and lock the blade in either of its extreme positions, limiting means, carried by the handle and disposed within a long notch in the blade for limiting the sliding movement of the blade in .the hanui, said blade bein longer'than the handle" and adapted to assume either of two extremeepositions, in either of which one end of the blade is retracted into the handle and disposed within itsrespective end thereof,

and the otherend is projecting therefrom.

3. An 'electricians knife comprising a slotted handle, a blade slidable in the slot in theha-ndle, resilient means disposed withe adjusted position, and a button mounted on the opposite sideiof the blade from the're- I 'silient means, said button being operatively --connected to the resilient means to cause it to in the handleo-n one side of the blade and engageable upon the'blade to lock the blade in disengage the blade and permit the bladevto slide in the handlei In testimony whereof v I have signed my I name to this specification.


Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2568353 *Dec 3, 1947Sep 18, 1951Miseta Jr FrankCombination paper-cutting tool
US3755893 *Oct 4, 1971Sep 4, 1973Nagaki KElectrician{40 s knife
US6247235 *Aug 15, 2000Jun 19, 2001Patrick F. LawlerSheathing slitter and cutter tool
US6745473Jul 18, 2002Jun 8, 2004Patrick F. LawlerCable sheathing slitter for a wire stripper tool
US6895674 *Aug 15, 2003May 24, 2005Jeffrey S. AiRoofing utility blade for roofing knife
US8739412 *Apr 23, 2008Jun 3, 2014Constantine M. GioiaUtility knife blade
US20080295344 *Apr 23, 2008Dec 4, 2008Gioia Constantine MUtility knife blade
US20110030224 *Aug 10, 2009Feb 10, 2011Desheng WangSide-push type composite putty knife
US20110030225 *Aug 10, 2009Feb 10, 2011Desheng WangPress-down type composite putty knife
WO2001019550A1 *Aug 31, 2000Mar 22, 2001Lawler Patrick FSheathing slitter and cutter tool
WO2005018885A1 *Dec 15, 2003Mar 3, 2005Jeffrey S AiRoofing utility blade for roofing knife
U.S. Classification30/162, 30/317, 30/143, 30/90.3, 30/90.4
International ClassificationB26B1/00, B26B1/08
Cooperative ClassificationB26B1/08
European ClassificationB26B1/08