US1651793A - Electric tool - Google Patents

Description

Dec. 6, 1927.

C. S. WEYANDT ELECTRIC TOOL Original Filed July 26, 1922 l .1 10. 100. 1101 10.01 10Q 1 .900H0N0NM000N0N000000 0000 0 0 0000000000000000 0 00000 000000 00 0 000o0000000000000000000000000000 0.000, 00N0N00 0000000000 0 0 Patented Dec. 6, 1927.

UNITED STATES oFFIcE.

GARL S. WEYANDT, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO CENTRAL ELEC- TRIO TOOL COMPANY, 0F PITTSBURGH, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

ELECTRIC TOOL.

Application led July 2G, 1922, Serial No. 577,720. Renewed J'une 8, 1926.

My invention relates to electric tools of the hammer class where an electromagnetically operated armature is caused to vibrate or reciprocate and operate a hammer, riveter, drill, chisel, or the like.

It is the object of the present invention to provide a tool' of the class mentioned which is compact, readily assembled and taken apart, well sealed against the admission of moisture to the windings and other interior parts, comparativelyl simple in construction, and reliable and eiiicient in use.

' Referring to the accompanying drawing, Fig. 1 is a central longitudinal section of my improved tool in its preferred form, and Fig. 2, a cross-section on the line 1lb-T11 of Fig. 1.

On the drawings, 2 designates a non-.magnetic cylinder or barrel in which the magnetic core, armature, or striking element l is reciprocable. rlhe barrel has at one end the external threads 4 and at the other end the internal threads 5, and is surrounded by two electromagnets 6 and 7 which have the respective windings 37 and 38 and whose magnetic circuits are separated by the libre washer 8. rlhe magnets have their magnetic circuits composed partly of the. steel casing` 9 and partly of L-shaped laminated steel field members v10 arranged radially .around the barrel. Each member 10 has a radial arm 11 lying against an end of a winding and an arm 12 dying parallel with the barrel between the latter and a winding. Each magnet has two annular series of field members with the free ends of the arms 12 of one series facing or opposite the correspending ends of the other series, providing air gaps wholly within the windings. rfhese ends are beveled and have lugs or extensions 13 in slots in the barrel 2. 'lhe outer ends of the arms 11 engage the casing 9 of magnetizable material.

14 is a ca i screwing on the threads 4 and having the liange 15 which bears against a fibre washer 16 imbedded in the inner wall 17 of the opening 18 in the handle 19. A. short fibre rin Y 20 lies between the cap and the handle an abuts against the washer 16. A fibre washer 21 abuts against the inner end of the handle and the ring 20 surround' ing the cap, and bears against the inner end of the casing 9. A fibre washer 22 lies between the cap and the casing, and also between the washer 21 and the arms 11nearest the handle.

The handle end of the barrel contains the reciprocable hollow core-stop 23 having its outer end closed and having the flange 24 working in the enlarged'portion 25 of the barrel and limited in its inner movements by the shoulder 26 and in its outer movements by the coiled spring 27 between the closed ends of the cap and core-stop. 28 is a set-screw threaded'in the handle and engaging the cap' 14 to prevent the accidental loosening of the cap.

29 is a non-magnetic nose piece or cap which engages the outer end of the casing 9, surrounds the outer end of the barrel, and has a flange 30 abutting against the said end of the barrel. A steel tool bushin 31 extends through the cap 29.. screws vinto the threads 5, and has the flange 32 which engages the washer 33 on the end of the cap 29.

34 is a tool, such as a riveting tool, or a drill, having the shank 35 slidable in the tool bushing 31, the tool having a shoulder 36 adapte to engage the bushing when the tool is in its innermost position, as shown in Fig. 1. "When in this position the end of the shankprojects beyond the inner end of the bushing and lies about opposite the outer circle of lugs 13, preferably about as shown in Fig. 1.. course, good results may be had if the end of the tool is not placed precisely as shown.

The end surfaces of the tool shank 35 and of the core stop 23 should be so disposed, relative to the air gaps between the lugs or tenons 13, that one end of the core 1 will project into one air gap when the other end of the core is at its extreme operating position adjacent the other air gap. rlhus, when the core engages the tool shank, its rear end surface should be adjacent the air gap of rear solenoid 6. When the core engages the core stop, its front end surface should be adjacent the front air gap of solenoid 7.' rlthe core l in its forward and backward AInovements closes each air gap or reduf. es each air gap to minimum length, and continues be yond the yposition of minimum air gap length.

The parts being assembled as described and shown, they may be very closely drawnv left end of the core and the extensions 13? of the left hand eld members 10. This pulls the core to the left and causes it to strike the shank 35 of the tool 34.' The winding 38 nowr becomes de-energized and the winding 37 is energized by another alternation or pulsation of current, which causes aflux to be generated to pull the core to the lright and against the core-stop 24, whereupon the second cycle of operation begins causing the core to moveto the left and to the right as before.4 These cycles continue as long as current is fed alternately to the windings in the manner described.

When a tool is not disposed in the hammer, and the core occupies its extreme t'orward position' against the tool bushing 31, the rear end of the core will bevforward of and out of the rear air gap or fiux region, and the core cannot then be moved 'by the rear solenoid 6.- If the hammer is held vertically while the vtool is out, the core will assume its extreme forward or lowermost position and will notl respond to the flux of the retrieving coil 6. This is an important and desirable feature since reciprocation of the core while the tool is not in position would impress severe stresses upon the tool socketiand tend to shear the threads 5 of the ba'rrel. Damage to the hammer structure is thus precluded, however, if the operating switch be inadvertently closed while the tool is not in operating position, since the solenoid 6.-will not actuate the core.

By having the inner ends 'of the eld members project into openings in the barrel close to the core 1, in its dierent positions, the shortest possible transverse air-gapsare provided. I prefer to make the windings` with a central internal annulus itting between the opposed ends of the arms 12 so that the flux density between the said opposed ends and through the core and the gaps at its ends is increased.

Certain features disclosed in this application, including, lamong others, the construction and disposition of the magnetic field members or laminations, and the rooperative relation of a movable core therewith, are claimed broadly in my co-pending application for a reciprocating electric motor, Serial No. 697,053, led March 5, 1924, a continuation of application Serial No. 527,037, tiled Jan. et, 1922; and certain other features disclosed herein, particularly the double solenoid field structure broadly, is claimed in my co-pending application Serial No. 541,517, liled ll/Iarch 6, 1922.

I claim- 1. In an electric tool, a non-magnetic barrel, a tool shank at one end of the barrel, a core-stop at the other end thereof, two axially alined windings surrounding the barrel, magnetic field members arranged around the barrel and within the windings, the lield members being interrupted to form short air-gaps Within the length of each winding, and a magnetic core reciprocable in the barrel and having its ends arranged to be drawn into the air-gaps alternately by by alternate energization of the windings.

2. In an electric tool, a non-magnetic barrel, a tool-shank at on'e end of the barrel, a core-stop at the other end thereof, two axiallyl alined windings surrounding the barrel, magnetic field members arranged around the barrel and Within the windings, the tield members being interrupted to form short air-gaps within the length of each winding, and a magnetic core reciprocable in the barrel and having its ends arranged to be drawn energization of the windings, theA magnetic members extending through the barrel-wall at the ends of the air-gaps.

3. In an electric tool, a non-magnetic barrel, a tool-shank at one end of the barrel, a core-stop at the other end thereof, two axially alined windings surrounding the barrel` Vmagnetic field members arranged around the barrel and within the windings, the field members being interrupted to form air-gaps within the length of each winding, and a magnetic core reciprocable in the barrel and havino its ends arranged to be drawn into the air-gaps alternately by alternate energization of the windings, the magnetic members .extending through the barrel-wall at the ends of the air-gaps and the windings having each an internal annulus in the adjacent air-gap.

4. In an electric tool, anon-magnetic barrel, a tool-shank projecting into one end of the barrel, and a core-stop projecting into the other end thereof, two axially alined windings surrounding the barrel, radiallyarranged field members, having radial arms at the ends of the windings and other arms lying between the windings and the barrel. the ends of the second arms for each winding being spaced apart Within the length of the windingmeans for completing the magnetic circuits between the 'ends of the radialI -into the air-gaps alternately by alternate Y arms, and a magnetic core reciprocable in the barrel between the tool-shank and the core-stop. A

5. In an electric tool, a non-magnetic barf. rel,'a tool-shank projecting into one end of the barrel, and a core-stop projecting into the other end thereof, two axially alined f windings surrounding the barrel, radiallyhave its ends magnetically drawn alternately into the said air-gaps.

6. In an electric tool, a non-magnetic barrel, a tool-shank projecting into one end of the barrel, and a core-stop projecting into the other end thereof, two axially alined windings surrounding the barrel, means providing magnetic circuits for the windings having air-gaps between the ends ofthe windings and wholly within the latter, and :i magnetic core having its ends arranged to be drawn into air-gaps of' the respective magnetic circuits from each end of its stroke.

7, In an electric tool, a non-magnetic barrel, a lmagnetic core reciprocable therein, a reciprocable core-stop in one end of 'the barrel, two axially-alined electro-magnets surrounding the barrel, laminated magnetic circuit members associated with each electromagnet and disposed radially around the barrel, a easing surrounding the magnets and fitting tightly over the laminated members to complete the magnetic circuits, a nose-piece closing one end of the casing, a tool-bushingextending through the nose piece and into the barrel, and clamping the nose-piece to the barrel, a tool-shank in the bushing and projecting into the barrel and into the path of the core, a closure for the remaining end of the casing, and means adjustably connected to the barrel for forcing the closures tightly against the endsof the casing and unit-ing the described parts into a rigid unit 8. In an electric tool, a non-magnetic barrel, a magnetic core reciprocable therein, a reciprocable core-stop in one end of the barrel, two axially-aimed electro-magnets surrounding the barrel. laminated magnetic circuit members therefor radially disposed around the barrel a casing surrounding the magnets and serving to complete the magnetic circuit between the laminated members, a nose-piece closing one end of the casthe nose-piece to the barrel, a tool-shank in the bushing and projecting into the barrel and into the path of the core, a closure for the remaining end of the casing, and a cap screwing on the barrel and having a fiange working on the outer face of the second closure to clamp thev described parts into a rigid unit.

9. In an electric tool, a. non-magnetic barrel, a magnetic core reciprocable therein, a reciprocable core-stop in one end of the barrel, two axially-alined electro-magnets surrounding the barrel, magnetic circuit members radially disposed around the barrel and serving to hold the magnets in place, a casing surrounding the magnets and tightly fitting the magnetic members to complete magnetic circuits therebetween, a nose-piece closing one end of the casing, a tool-bushing extending through the nose-piece and into the barrel, and clamping the nose-piece to the barrel, a tool-shank in the bushing and projecting into the barrel and into the path of the core, a closure for the remaining end of the casing. a cap screwing on the barrel and having a flange working on the outer face of the second closure to clamp the described parts into a rigid unit, and a spring to urge the core-stop toward the. core and held under tension by the cap.

10. In an electric tool, the combination with a winding, of an inner shell built up of' laminations to constitute a portion of the magnetic circuit for the winding and an outer shell serving as a casing for the tool and as a portion of the magnetic circuit for the winding.

11. In an electric hammer, the combination with a movable core member and an actuating coil therefor, of a plurality of' members constituting the internal magnetic circuit conductor and an enclosing tube constiltuting the external magnetic circuit conductor, said, core having such characteristics and being so slitted as to provide paths of relatively high resistance to electric currents and relatively low reluctance to magnetic flux.

l2. An electric tool of the reciprocating motor type comprising a barrel provided with an enlarged flange-like portion at each. end constituting a shoulder onI the barrel, one portion being externally threaded and the other end of the barrel being internally threaded, magnetic field members seated on the barrel. and snugly held in osition against said shoulders by tenons fitting into the barrel, solenoids associated with said magnetic field members, a core responsive thereto, a casing fitting over the field members and enclosing Ithe solenoids, a nose piece fitting over one end of the barrel against the field members, a tool socket for clamping the nose piece to the barrel, a bumper in the bther end of the barrel, a handle piece fit- "ting over the same end of the barrel to noids in position and locking portions fitting into the barrel, said members being radially disposed around the barrel, a casing fitting over the limiting portions of the magnetic field members to enclose the solenoids and to serve as a magnetic conductor between the field members, means fitting over the ends of the barrel to enclose the ends of the solenoids, and means for locking `said means in position and also to clamp the casing between said means to hold the several elements in a compact unit.

14. An electric tool of the reciprocating motor type comprising 'a barrel or guide, a core member freely movable therein bctween predetermined limits, two solenoids axially alined around the barrel. magnetic field members for the respective solenoids to concentrate the magnetic fiux of therespective solenoids atpredetermined regions of the path of travel of the core, and a casing of magnetizable material enclosing said coils and their field members and substantially closing the magneticcircuit of' each of said coils.

15. An electric toolcomprising a reciproeating magnetizablecore, a field winding, a plurality or" groups of laminations spaced circumferentially of the axis of movement of the core, and a casing of magnetic mate- 'rial enclosing said winding and groups of laminations and forming with said laminations a relatively fixed field structure with respect to which said core'is movable.

16. An electric tool comprising a reciproeating magnetizable core, a plurality of field windings disposed in different positions along the path of movement of said core, a plurality of circumferentially spaced groups of outwardly extending laminae in the magnetic circuit of each of said windings, an air gap for each winding between the ends of groups of laminations approaching each other.longitudinally of' the movement of said core. and an enclosing casing of' magnetic material substantially closing the magnetic circuit between the outer portions of the groups of' lamine.

17. An electric tool Comprising a, reciproeating magnetizable core, a plurality of field windings, and a plurality of circumferentially spaced groups of outwardly extending laminas in the magnetic circuit of each of said windings, the adjacent groups of 1aminte for the different windings being separate from each other.

18. An electric tool comprisin a. reci roeating magnetizable core, a plura ity of: eld windings, and a plurality of circumferentially spaced groups of outwardly extending llamina@ in the magnetic circuit of each of said windings, the adjacent laminas of the different windings being spaced from each other llongitudinally of the movement of said core.

(fg/"19. An electric tool comprising a reciproeating magnetizable core, a plurality of field windings, a plurality of circumferentially spaced groups of outwardly extending laminae in the magnetic circuit of each of said windings, the adjacent groups of lamin for the different windings being separate from each other, and an enclosing casing of magnetic material substantially closing the magnetic circuit of each of said windings.

20. A percussive tool of the reciprocatin electric motor type comprising front an rear solenoids, a magnetizable core structure actuated by said solenoids, laminated field members for concentrating the magnetic fluxes produced by each solenoid in an air gap within the length of the solenoid, a yielding back-stop adjacent the air gap of the rear solenoid,`a tool bushing adjacent the front end of the motor, and a tool shank extending through said bushing and terminating adjacent the air gap ofthe front solenoid, the length of said core structure, the length of the air gaps and the distance between the air gaps being such that the core structure is not actuated by the rear solenoid when said tool shankjs removed and said core structure engages said bushing.

21. An electric tool comprising a tool shank and a core stop adjacent opposite ends thereof, a plurality of field windings, magnetizable field members for each winding spaced from each other longitudinally andV approaching each other longitudinally to form an air gap, and a magnetizable reciproeating core engaging said tool shank and core stop and movable past the positions in which it reduces said air gaps to minimum length.

22. An electric tool comprising a reciproeating magnetizable core.` a plurality of rgroups of circumferentially spaced and outwardly extending laminae disposed along the path of said core, a field winding positioned between adjacent groups of lamince7 and a easing of magnetizable material engaging the radial extensions of said laminae which project beyond the outer periphery of said winding.

v 23. `An electric tool comprising a reciproeating magnetizable core, a plurality of groups of cireumferentially spaced and out wardly extending laminee disposed along the path of said core, a plurality of axially aligned windings, each positioned between adjacent groups of laminae, and a casing of 5 magnetizable material enclosingrsaid Wind; ings and engaging the radial extensions of the outwardly extending lamine which project beyond the outer periphery of the windings.

In testimony whereof I hereunto affix my signature this 22nd day of July, 1922.

CARL S. WEYANDT.

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