US2457829A - Power driven hand racksaw - Google Patents

Description

7 Jan. 4, 1949. c. D; MILLER POWER-DRIVEN HAND HACKSAW Filed June 3 1944 Patented Jan. 4, 1949 j UNITED" @FFICE Romain-DRIVEN mensaw Charleen. Miller, Davenpo1'.t,.fawa.= I Application limes;- 1944; SbvihUNb-i scat-tr Julianna: (ooze-ta), 1 W (Granted; lindfi the. act 11sec, as.

The invention described; herein may. menu, facturedl. and. used by. or tor the. Governmentibr gov nmentali purposes withoutthe payment. to meofa'ny royalty thereon. v I

I. The present invention. relates generally to. the. art of .powersdriven. machinery... More particiu l'arly'. it. pertains to a smallpowen-operatedl tool commonly referred to as. a hacksaw,v which. type of tool. is. generally. designed for. manual opera-=- tion-w. 'Inl'thej normal. course of 'operation.,.o1.f agmaq chine shop onfmanuiacturi'ng, plant. therev are many instances. which. arise. in which. it. becomes necessary tdgcut. ofi' short sectionsof. material. such as s' teel'gbar. stock; hollow rounds,.or. other elements 'aI'icLwhich operation because. or; its. smallscale. is not generally performed.v con.- ventional' power-driven... machineryc InQthe. past. it has been. the usual practice toperform this. operation. manually witha hand hacksaw. for, while. power-driven. hand. hacksaws. designed. to cut. bar stocklanct the like havebeenknown prior to. my .inventi'on they have. not. been i highlysue. c'eslsful. forvari'oli's. reasons-ihcluding faults. at: tributable primarily to. their: drive. mechanism. For example, prior'unitshave either employeda considerably restricted stroke. or else. have; been rendered awkward and cumbersome? by' the in;- corporation of bulky parts to provide. amoi'e; satisfactory stroke; also prior devices;have .normally not provided an even stroke as, far as. speed of travel during. a complete traverse; ot' the work by the operative portion. ofthe blade. is concerned. Although each offthe" individual operations in which it has been necessary or desirable for a workman tospend' his time manipu'e lating a hacksaw manually, when considered. by. itself, is of relatively unimportant scope, itis;

nevertheless true that taken in the. aggregate...

such small jobs mount up over. a. periodioff time. and, for example, over'a years operations will; assume major importance as far as. time. and' manpower are concerned. It is accordingly an important object. of: the. present invention to provide a small'powen-driven. hacksaw which may conveniently andefiectively be employed in the performance of. suchsmalt jobs as cutting off the ends ofbar. stock. or. other raw materials and yet. whichis not sabullty that it may not be conveniently handled. and. transported from place to place within the-shop. or supply room. It is an object of my invention to provide such a power-driven hacksaw which will materially speedup the time required for performing the" operations mentioned; above and wl'iichwill perl 2t. form the "s'ajmelwitha minimum expenditure of eifortonrtliepartoi; the. workman.

rhfinttlaei:- object oiiimy invention is to provide ahacksawhoff. the,.type alluded. towhich has a stroke comparable i 'ntlength. to the normal. stroke.v

inmanual operation.

Yeti. anotheriohject. of; the invention isLto pro.- videa power-drivenhacksaw. inwhich. the speed. off'the. stroke is substantially constant.- throughout. itscourseofltravel. a

Another, object. oi: my invention resides. thefact that'ttheappiication of. power. to the. sawing. operation may; beefiicted. by. means; of very slight. modifications. in anel'ectric motor. of conventional; or: standardmanufactura.

It isjanother object of my invention to provide j a. guiding. handle for a. power-driven. hand. hacksaw which is, adapted to be either.- gripped or pushed. againstb'y the. operator, depending upon the circumstances oflfoperation.

Still anotliler. object: of my ir iventi'rm v is to. provide? a. frame structure. which willflbe. light in Weight.and. yet sufliciently rugged to withstand. the. hardabuse to" whichshop tools of'this type.

are gje'neriallixlsublectedt Iii-tl'ii'ssame connection air... portantgobject'to provide.stro'ng.lightwerghtiltearing's ,ror. permitting. easy. reciprocation oftlre hacksaw" blade and" to, provide a simmeyet reliable mechanism for imparting, the necessary reciprocatory motion to aid; blade.

still" furthefiobject of my invention is the nrovision"; or'la. hacksaw, or tnetype mentioned in which th" made is; supportedendreinforced; by a comparable to that employed in standard mamaly' operated hacksaws. while" yet being. drivenjad cent its top sothat the lower portion dff'tlf i'e saidjrramearrdtm b'la'd'e are: spacedsubstahtiaiim fromthe, power-providing. adjuncts Referring now more particularly to Fig. 1 of the drawings I have illustrated a power-driven hand hacksaw having a rotary prime mover section and a reciprocating operating section. The power required for operation of the reciprocating section may be obtained from an electric motor I of conventional design having a hand grip 33, an electrical connecting cable 34 and a start-stop switch 42. In order to provide a suitable speed reduction I have also provided a reduction gear housing 35 formed as an integralportionof the electric motor I and containing suitable reduction gearing for driving the hack'saw blade.

Since the specific details of the electric motor and reduction gear train form no part of my therein.

' roller bearing designated by the numeral 20, having an axle 22 and adapted to operate within a groove or trackway formed by two guiding mempresent invention I have not illustrated them in detail and they may be of any desired or conventional design. The reduction gear chamber is provided at its right-hand side with a stepped flanged structure 3 which is secured thereto by means of stud bolts or socket screws'2. The righthand face of the flanged member 3 is machined and suitably bored and drilled to be joined toanother flanged section 4 by means of a plurality of socket screws I6. The flanged member 4 has secured to its right-hand portion as by means of riveting or welding a tubular shaped frame member or drive housing generally designated by the numeral 23. A ribbed bracing structure 5 having a plurality of ribs designated by reference numeral '43 is secured over a portion of the housing member 23 by means of riveting or welding and likewise is provided with a flattened base portion 5 adapted to be secured to the face of the flanged member 4 in order to provide for sufficient strength and rigidity in the housing. The flanged base members 3 and 4 are suitably bored at the center thereof to receive a stub shaft 36 extending from the reduction gear housing 35 and driven by the electric motor I. This stub shaft 36 extends through the base plates 3 and 4 and is suitably squared or otherwise keyed in such manner as to be suitably received in positive driving relation in the internally squared or keyed end of the main driving shaft 9. A set screw I is provided in the hollow end of the main drive shaft 9 and bears against the stub shaft 36 in order to prevent any relative motion therebetween. A bronze bearing member 6 is provided within the central aperture of the flanged member 4 and provides a bearing surface within which the enlarged hollow end of the. main drive shaft 9 may rotate. The main drive shaft 9 is also provided with a similar bronze bearing member II within which its reduced right-hand portion is journaled. The bearing member I I is positioned within a flanged end plate I9 which is secured as by means of machine screws 31 within the outer or right-hand end of the main housing 23. The main drive shaft 9 is provided along the outer portion of its length with an endless female thread for a purpose which will hereinafter be apparent.

Referring again to Fig. 1, it will be noted that I have provided a blade carrying frame 3| of'steel or other suitable material which is formed and dimensioned in such manner that a standard hacksaw, blade may be secured within the arms thereof. For this purpose I have provided brackets at the extremities of the two lower armsof said frame, said brackets carrying bolt and pin assemblies which are adapted to be engaged within the ends of the hacksaw blade. The bolt I! at the right-hand end of the frame is freely slidable within its bracket, but is of course limited in its bers- I8 which are secured to the inside of housing 23 as by means of conventional machine screws I9 and 2I. The frame member 3I is also constrained to longitudinal movement by virtue of a structure which is more clearly illustrated in Fig. 3. As illustrated in that figure the main frame 3i is provided with longitudinal grooves on each side thereof as indicated by reference numeral 38;which grooves are adapted to engage the sides of another groove formed along the bottom portion of the main housing 23. The effect of this assembly is thus to prevent any downward or outward movement of the main frame 3I and its associated mechanism from within the housing 23. It will be noted that in the normal operation of this apparatus the reaction which will naturally occur from pressing the blade against a piece of material to be sawed Will be such as to apply a force upwardly against the top portion of the housing 23, which force will of course be taken care of by the roller bearings 20.

Referring again to Fig. 1, it will be noted that suitable bearings 8 and 32 are provided within the upwardly extending arms of the frame 3I within which bearings is journaled the main driving shaft 9. The purpose of the structure which has been thus far described is to provide a guiding and bearing structure to accommodate the reciprocatory motion of the hacksaw blade which is carried within the main frame 3|. The means of imparting this reciprocatory motion to the hacksaw blade will now be described.

' As set forth above, the main driving shaft 9 is provided towards its outer end with an endless thread! Such a'grooved endless thread has been known previously as a mechanism capable of converting a continuous rotational movement in a single direction into a reciprocatory or back and forth motion in opposite directions. In other words, if an external member is applied around the shaft 9 having a projecting portion depending withinthe'grooved portion of said shaft and the shaft is continuously rotated, it is only necessary to prevent rotation of the external member in orderto-impart thereto a continuous reciprocatory motion: This has been accomplished by applicant in the manner illustrated more clearly in Fig. 3. As illustrated in the latter figure, the outer upwardly extending arm of the main frame III is, provided with an embossed portion on its right-hand side. This embossed portion is drilled so that'the axis of its bore intersects at right anglesthe axis of the main drive shaft 9. The bronze bearing member 8 is also cut away at this point to provide for the insertion therein ofv a stud 25 swivelled within a base member 26 and having a projecting portion 39 suitably cons;wivel member 2 5 having its follower portion IIB is most; olearly=i1lustrated r in the 'detail'edel 'lgi :4.

Referring now to Ffig'stl andQEoftheidraWings I have willustrated a .guidingashandle i40awhic forms ansimportantzpartof mwpresent invention. This guiding handle is adaptedrtoibeifonmed of a? single piece of neither SOIidt or :hollowmbar 1 stock to rest :against the outer top :portioneof hack saw frame while. theycare engaged; in usingzth same. .At thevsameztime; it is alsoeknowrrztha certain other persons;followrthegpracticeaof grasp ing the outer portionpf theframe msingzthe han and fingers for this purposem;Itwill-thus-beclearr that I have provided a; bracket. or handlerwhich-ris so shaped that it may be employed in either mane" ner and is thus adaptedr the usewof any individual regardlessof his practice inthisrregard; 2

The operation of the device is as follows: The

operator may for example grasp the assen'ibly by taking hold of the handle 33.-with his right hand and of the handle 40 with his left-hand; 2 Operation of the starting switchrfl causes the electric motor I through the reduction gear train contained within housing 35;%andithe.=stub driving shaft 36 to apply a rotationalforceto themaim driving shaft 9. the main driving shaft 9 is converted "into a reciprocatory motion of the.sframed l -bymeans of the engagement of the follower portion 39 of the-*- swivel member within the endless thread formed in the outer portion of -the maimdrive shaft 9. The length of strokeof the hacksaw blade is determined by the length'of the.:endless thread. As the reciprocatinghacksaw bladeris pressed against the surface of a piece of material." to be cut, the roller bearings 20,.reactingr-against the, main housing 23, will absorbthe' upwardre-= action from the'bla'de. The friction dueito-qthe, reciprocatory motion of the frame .31 is absorbed! in part by the bearings 8 and 32 which slidetalong theoutside of the rotating maineidrive shafte9.

The rotational friction of the main drive shaft 9 will be largely absorbed by the end bearings 5 and I l Within which it is journaledie-During thecutting, operation the operator may prefer toihold the'assembly merely by means of grasping the handle 33 and using the handle as an abut.-

ment against which the palm of the left hand may be presesd in order to guide and force the saw into the work. The tool may be conveniently plugged into any suitable electrical outlet by means of the cable 34 and may be turned on and off at will by means of the switch 42. Also the saw blades may be quite readily changed in a conventional manner.

An additional attribute or merit of my device in its preferred form is the fact that it may be employed for manual operation, as well as being power-driven. Very frequently it is desirable to start a cut by manually drawing the blade over the Work a plurality of times in order to locate it at exactly the desired point and my saw will function in this capacity without driving the motor in reverse, thus permitting the blade to move. If any difficulty be experienced in preventing independent blade movement and accompanying reverse driving of the device, the same may be remedied by providing a slightly high fric- Th'e'rotational force applied to r fonexample as at one of .the junotuitessat whici the saidag roove reverses iits directionr. Withsuch construction the bladealso' tends to normally hal 5 inthe rsametposition' eachnitimemthatl the prim mover: is iStOIJDQdrn-Y Myai theory. concerning: 1th

illustrated in the ..-drawingvtnumeralrfi 9): is em ployed; it is brought to a haltxin :said. highfriotransverselyoftheapower shaft Sin the returning 5, ,bend.-:.:of the Lthread groove: so that i it in teffectiis in 5,3; fidea d centerirposition. I doenot, however wish; togsin any-sensegxbe limited by thisatheory sinceuit is conceivab-lectha't I amlin error therein ,,Iny 'saw functionsaxin thelmanner indicated; 1".

understood that various modifications;,deviaes; ,tionspandidepartures occurzto one-skilled in "theiartiandt l accordingl'g do not,rintehdmminven tion to bezlimited-to .the;specific Iembodimentxdise closedrbut only in accordancepwithtthe :followingn;

claimsr;

I claim: :1

primewmover; --a tubular elongated;housing;

and -having ,pnits periphery spirally extending drive shaft, 1a swivelly mountednfollow. member supported by .-said ,hanger and adapted to travel $5 to and fro in engagement-with said guidemf the drive shaft astthe :latter is rotated :whereby Said frameois propelledialong a reciprocatoryrpathda :z low:fric tion=means on-said hanger member. ridingm in rengagement' with the inner surface a of r: said-m 50, housingrfor: transmitting -to said, housingmthrustl appliedwto said frame dlllfillgethfi:OpBIZttiOITOf-lihfi saidawhacksaw, flange means-for attaching: said. tubular? elongated hOllSing:.:l30 "theysaid rpri'me t mover; and structure;forreinforcing said housing;

adjacent said flange means comprising an elongated tubular section receiving a portion of said housing and having flange structure adjacent one end abutting said first flange means and a plurality of rib members extending longitudinally of itself outwardly from its said flange.

2. A power-driven hand hacksaw comprising a prime mover, an elongated tubular housing, a drive shaft rotatably mounted in said housing and having on its periphery spirally extending guide structure doubled back on itself to provide an endless and returning guide, means operatively connecting said drive shaft to said prime mover, a frame for mounting a saw blade or the like, a hanger member projecting from the general top portion of said frame and extending into said housing through a narrow slit in the latter, a bearing on said hanger rotatably receiving said drive shaft, a swivelly mounted follow member supported by said hanger and adapted to travel to and fro in engagement with said guide of the tionrareaxatapointralong thet'spirairgroove; such mannerdn which reverse driving of the? motor :is i 1. positivelyripreventedwhen rhighifrictioli'r..area': is is provided at:onezof the turningipoints of i theispiral locfgrooveiiis thatswhen. a follower such as =-the" typ,

tionrarea-dnta position extending substantially and'theizfactremains that-regardlessaof theareasoni While: I- havei'illustrated andudesc-ribed, a preiez'"; ferred embodiment ofinventionrin theipresent a drawings rand specification; it is "to cube: clearlyi 1. A power-drivemhandhacksaw[comprising a. a

drive shaft as the latter is rotated whereby said frame is propelled along a reciprocatory path, a low friction means on said hanger member riding in engagement with the inner surface of said housing for transmitting to said housing thrust applied to said frame during the operation of the said hacksaw, and a handle member comprising a connecting section, an arm projecting from one end of said connecting section and generally normal thereto but having its extended end spaced laterally of said connecting section to one side, another'arm projecting from the other end of said connecting section at an angle less than 90 and having its extending end disposed laterally of said connecting section to the other side, and angularly disposed fastening lugs on the extended ends of said arms, said handle being mounted upon the said elongated tubular housing in a manner such that the fastening lug of said first arm is disposed generally to one side of the housing and the fastening lug on the other said arm is disposed adjacent the top of the housing and further removed from the prime mover than is said first fastening lug.

3. In a power-driven hand hacksaw, an elongated tubular housing having a slit extending at least a substantial distance along its length, a drive shaft rotatably mounted in said housing and having on its periphery spirally extending guide structure doubled back on itself to provide an endless and returning guide, a frame for mounting a saw blade or the like, a plurality of spaced apart hanger members projecting from the general top portion of said frame and extending into said housing through the slit theremitting to said housing thrust applied to said frame during operation of said hacksaw, and a swivelly mounted follow member supported by one of said hanger members adapted to travel to and fro in engagement with said guide of the drive shaft as the latter is rotated.

4. A power-driven hand hacksaw comprising a prime mover, an elongated tubular housing, a drive shaft rotatably mounted in said housing and having on its periphery spirally extending guide structure doubled back on itself to provide an endless and returning guide, means operatively connecting said drive shaft to said prime mover, a frame for mounting a saw blade or the like, a hanger member projecting from the general top portion of said frame and extending into said housing through a narrow slit in the latter, a bearing on said hanger rotatably receiving said drive shaft, a swivelly mounted follow member supported by said hanger and adapted to travel to and fro in engagement with said guide of the drive shaft as the latter is rotated, whereby said frame is propelled along a reeiprocatory path, a low friction means on said hanger member riding in engagement with the inner surface of said housing for transmitting to said housing thrust applied to said frame during the operation of the said hacksaw, and a handle mernber comprising a connecting section, an arm projecting from one end of said connecting section having its extended end spaced laterally of said connecting section to one side, another arm projecting from the other end of said connecting section and having its extending end disposed laterally of said connecting section to the other side, and angularly disposed fastening lugs on the extended ends of said arms, said handle being mounted upon the said elongated tubular housing in a manner such that the fastening lug of said first arm is disposed generally to one side of the housing and the fastening lug on the other said arm is disposed adjacent the top of the housing and further removed from the prime mover than is said first fastening lug.

CHARLES D. MILLER.

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

UNITED STATES PATENTS Number Name Date 158,932 Gilbert Jan, 19, 1875 404,017 Robinson May 28, 1889 436,804 Roberts Sept. 23, 1890 699,995 Whitney May 13, 1902 924,509 Taylor June 8, 1909 1,645,646 Gray Oct. 18, 1927 1,763,500 Bowen June 10, 1930 1,830,580 Wappat Nov. 3, 1931 1,919,323 Blum July 25, 1933 1,993,797 Peterson Mar. 12, 1935 2,329,729 Saucke Sept. 21, 1943 2,330,618 Plumb Sept. 28, 1943 FOREIGN PATENTS Nur ber Country Date 100,137 Sweden Oct. 29, 1940

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