US2438777A - Percussive tool - Google Patents

Description

March 30, 1948. w. H. DEAN 'PERCUSSIVE TOOL Filed June 20, 1945 2 Sheets-Sheet 1 March 30, 1948. w. H. DEAN PERCUSSIVE TOOL Filed June'ZO, 1945 2 Sheets-Sheet 2 Patented Mar. 3 0, 1948 UNTfED STA'ES NT *form-.cle

Application June 20, 1945, Serial No.600,495

` In Great Britain June 26, 194e 3 Claims.

This ,invention vrelates* to percussye itools, and l l like.

@ne lobject of my Ainvention is to Vprovisie a vpower-operated 7percussive 'tool with means whereby `:the .application of power `to the tool .is automatically ycontrolled Vas Kthe tool is applied .tota-nd removed .from the work.

.A further object is to `provide, in combination with .said tool, .improved power-driven reciprocating mechanism .and .an r.improved iiexible drive whereby the lreciprocations ci said .mechanism are transmitted to `,the tool.

With these and Aother objects in vliew, `my invention consists of the novel features -of construction herein escribejfi `and 'illustrated and yspecifically set outlin the .appended claims.

will fully describe my invention with reference 't'o the accompanying 'drawings wherein Figure "lis va longitudinal section of one ,construction voi `tool in `accorcia-nce with my invention ttted with "a, riveting set, the Vworking parts ofthe tool -being shown in "their operative posin tion-s;

vFigure-l?. lisa sectionon-the line 'I1-*II `in Fig. 1

4"Figure -3 is a vpart lsimilar Iview to'Fig. 1 showing fthe working vparts `of the Atool in their in- '.operative positions; and

-Figure i4 is :a section on the line IV-J-IV in 'Eligure L5 "is 1a view llooking -on Athe right-hand end of Fig. 1, and

vFigure .6 vis an velevation of fa chisel 'with its 4holder Aand :tommy-bar which .can be substituted .forithe rivetsetofgliigs. .1 and 3.

Figure :7' fis an :elevation yof a .power-driven 4recipe@eating Amechanism and flexibletransmission AIth'e ;1atter;in section) lsuitable .for .actuating the 'tool illustrated finililigs. v1to;5,the cover of `the :casingiof lthe .mechanism being 'removed for clearness and `the working parts thereof being shown'in positions corresponding yto those of the Working parts of fEigs. l and y2;

.'Figure js-:a plan section onthe line VIEI4VLII .in Fig. 7 zand .Figure ,9 is .a similar 'View to `Fig. .7 showing :the 7wmking ,-parts of the :reciprocating :mecha- `nism in ypositions :corresponding to these of the working Parts of Figs. 3 and 4. Y

Referring to Rigs. l .to :5 .of the drawings., in .the riveting tool :therein illustrated, iIll is -a pis- -ton reciprocating in a cylindrical barrel kLI and having at its forward end aand integral 4with it a hammer l2 whichfooaots with the tapered rear end I3 lof a work-engaging membensuch fior instance as acylindrical rivet Vset IA, the ziorward `portion t5 of which projects through the ``nose it of a-worknghead IFI. The latter fis hollow vand contains within it a xcylil'uir-ical block I8 which is free to Aslide in a @direction @perpendicular to Ythe longitudinal axis of the itool vand y,is

pressed out of concentricity with said axisby .a

ball I9 on which bears a spring `Jill -fprovideclfine socket 2l inthe working headclosed by ascrewed plug 2v2. :In-to the i'rear end .of the'worliirllii :head Ifl a fiangeelcover 23 is screwed, said cover-being provide-cl with a central :hole 24 through .which 'the forward -end of the :hammer I2 enters the `working head. The block L8 is `provided. with a central socket 25 tapered .to .correspond with the rear fend I3 of :the Vrivet set, and `lsaid. block is also provided with ya central vaifierture y26 of diameter slight-1y greater Ithan that of the .hammer I2. 2l is a ring for locking the cover .23.011 .the Vforward. .enel of the barrel 4I..I and .so securing `the work-ing head :ITI thereon.

A spring l28 is disposed ,between the .nose .I6 of the working head 1anni vla washer .29 .onthe forward portion .I5 of the rivet .setcoacting with .a securing .pin 3l) therein, :said spring `serving to maintain the rivet set inits iully .projected .position when not fin use. When the .rivet set is in yits -ful-iy projected position, its `tapered ,rear end' I3 is clear of the tapered ssocket .25 in .the block I and, on the hammer l2 :being retracted to the rearmost extremity of 'its stroke, the forward end .of 'the hammer .is clear of :the aperture 2t in the 'block though still projecting into the hole 2:4 in `the 'cover 'ilhe -,disengagement -o the rivet set 'and .of `the T,hammer imm the block la allows the block, uriner fthe pressure :of lthe spring 2S and ball I 9 to :more into :an @eccentric position in relation *to :the axis 'of ythe tool, `as shown in Figs `3 and .4. in 'this T.posit/i011., "the blows of the hammer 5I2 are w,absorbed :bythe 'block I8 and ethe working head zIc'l, the face of the hammer Vmerely Jchattering against :the :ma-rgin of the aperture 2.6 'in the ahlQck.

When however the forward end Iii of t-he rivet set is applied with vpressure-toa.rivet (indicated in `dotted lines at 3| yin Fig. 51.1), th'eerivet Set Ais I.pressed .in `against the springf and its tapered Vinto the barrel II of the tool.

the block I8 permits the hammer to reciprocate through the hole 24 and aperture 26 and strike the opposed face of the rivet set thereby imparting the percussive blows of the hammer through the rivet set to the rivet 3|. The action persists so long as the forward end of the rivet set I4 is pressed against the rivet 3 I, but relief of rearward Y strikes the rear end I3 of the rivet set, provided axial pressure on the rivet set immediately perinits projection thereof by the spring 28 whereupon the rivet set disengages th'esocket 25 and the block resumes its eccentric position.

It will be understood that a chisel, suchas.

that illustrated at 32 in Fig. 6, may be substituted for the rivet set I4, the shank 33 of said chisel being received in a socket 34 in a toolholder 35 provided with'a tapered rear endV 36 identical'with the rear end I3 of the rivet set I4 and operating in similar manner in th'e working head I1. vIn place of the pin 39 co-actin-g with the spring-pressed washer 29 of Fig. 1, a tommy-bar 31 of suitable length is screwed into a'tapped hole 38 in a widened washer 39 on the tool-holder 35, the end of said bar projecting through a hole v:lil in said holder and abutting against a at 4I on the shank 33 of the chisel thus securing the chisel and enabling it to be rotated during the drilling operation. The washer-39also forms the bearing surface for the forward end of thespring 28 on the nose I6 of the working head shown in Figs, l and 3.

y, ItY may be preferable that the working h'ead I1, complete with its nose I6, rivet set I4, washer 29, spring'28, block I8, plug 22, spring 20, ball I9 and flanged cover 23, shall be manufactured as a sealed assemblage which can be screwed as aunit onto the forward end of the barrel II of thegtool and locked thereon by the ring 21, and that the chisel 32 sh'all be incorporated in asimilar sealed assemblage rwhich can be substituted as a unit for the rivet set carrying working head of Figs.l 1 to 5.

reciprocating kmechanism hereinafter more par` ticularly described, mounted within a casing 42, Figs.Y 7, 8 and 9, and coupled by a flexible cable 43 with a non-reciprocatory flexible sheath 44 to the rear end of the piston I0. Y

The forward end of the cable 43 is provided with a spherical-headed nipple 45 engaged in a slot 46 in the rear end of the piston I0, said cable Vpassing through a lian-ged bush 41 in an externally-threaded flanged sleeve 48 projecting The sleeve 48 is screwed into the rear end 49 of the barrel I I and into the centre portion 50 of a handle 5| Vpositioned to provide a balanced support for th'e tool` `A powerful helical compression spring 52 extends between the rear end 49 of the barrel IliandV the rear end of the piston I0. The bush 41 forms asocket for the forward end of the sheath 44 which retained in the rear end of` the sleeve 48 by a terminal 53 provided on the Yend of a iiexible tube 54, said. tube, adjacent to the handle 5I being provided with a guard spring 55 the forward yend ofV which engages in a helical groove around the rear end of the flanged sleeve 48 as shown in Fig. 1, said rear end and the guard spring being enclosed in a socket 56 in the rear end of the handle 5I of the tool.

In operation, the stroke of the piston I6 towards the right under the pull of the cable 43 compresses the helical spring 52 and Vcompletely withdraws the hammer I2 from the aperture 26 in the block I8 into the position indicated in Fig. 3. The stroke of the piston towards the left is .the operative stroke wherein the piston is projected by its spring 52 until the hammer I2 that said rivet set is pressed against the work and its rear end engages sufficiently in the tapered socket 25 in the block I8 to retain the axis of said block concentric with the axis of the tool as shown in Fig. 1. If th'e rivet set is not pressed again-st the work, it is projected by its spring 28 and its rear end is disengaged .from the block I8 which automatically assumes the position shown in Figs. 3 and 4, subsequent blows of the hammer being taken by the rear face ofthe block I8, the

blows then occurring being only minute.

Referring now to the quick-return reciprocating mechanism shown in Figs. 7, 8 and 9, 51 is the shaft of Va suitably supported electric motor (not Y shown), said shaft projecting through' an oil seal 58 in the rear Wall 59 of the casing 42. The side walls of the casing are flanged as shown Vat 68 and a removable cover 6I (Fig. 8) is attached to said flanges by screws (not shown) disposed atV driving pin 66 which' coacts with the under face` 61 of a lever 68 pivoted on a fulcrum pin 69 provided within the bottom of the casing. The lever 68 has a pinV Ill projecting from its side which engages a link 1I havin-g parallel sides united by rounded ends, its right-hand end being slotted at 12 to receive the shank 13 ofa spherical-headed nipple 14 on the opposite end of the cable 43 to the nipple 45 in the piston I0 `of the tool. The pin 10 is connected by a helical tenV sion spring 15 to the end of a stationary support 16 in the bottom of th'e casing 42 remote from the fulcrum pin 69, said spring maintaining the under face 61 of th'e lever 68 constantly against the eccentric pin 66 of the flywheel 65. The eX- treme positions of the pin 66, lever 68, pin 10 and nipple 14 are shown in Figs. '1 and 9 respectively, said positions corresponding to those of the working parts of the tool as shown in Figs, 1 and 2 and in Figs. 3 and 4 respectively. Y

The cable 43 passes through av threaded bush 11 screwed into the lower right-hand end of the casing 42, said bush being flanged at 18 and tted with a tubular sleeve 19 carrying a nipple 86 suitable for the application of the nozzle of a lubricant gun. Oil or light grease forced into said nipple passes through a port 8|, an annular space 82 and a port 83 into a space 84 around the end of the flexible sheath 44 which is re ceived in a socket 85 in the bush 11, said bush being screwed onto the terminal 86 of the Ailexible tube 54 within which the sheathed cable 43 is contained.l The end of a helical guard spring 81 engages a helical groove around the bush 11 beyond its flange 18 and Uenclosesthe 5 flexible tube 54 for a short distance from the casing 42.

The position of the piston l in the barrel Il can be adjusted, by holding said barrel rmly by the working head I1 and slightly rotating the handle 5I which serves as a locking nut on the thread of the sleeve 48 within the centre portion oi the handle, whereupon said sleeve can be adjusted in relation to the rear end of the barrel and ire-secured by returning the handle until it bears against said rear end.

It will be observed that the reciprocating mechanism in the `casing 42 operates in an oil bath and that lubricant under pressure may be fed, when required, through the nipple 80 into the tube 54 and through same into the barrel l! of the tool, so that the drive throughout its length and the piston in said barrel receive adequate lubrication.

It will also beobserved that the disposition of the pivoted lever 58 in conjunction with the eccentric driving pin S6 on the ywheel 65 on the motor shaft 5l results in a quick-return movement of the cable 43, and that the sliding of the spherical-headed nipple 14 through the end wall of the link 'li permits the cable 43 to relax freely, thereby eliminating all mechanical stress from the point of its attachment.

What I claim and desire to secure by Letters Patent is:

1. A power-operated percussive tool comprising a reciprocable hammer, a working head secured to said tool, a work-engaging member supported in said head for reciprocable movement in axial alinement With said hammer, a transversely movable block disposed Within the head between the hammer and said work-engaging member, resilient means in engagement with said block and normally retaining it in position to prevent contact of the hammer with said work-engaging member, said block and Workengaging member having cooperating means whereby the block may be moved against the tension of said resilient means to establish contact of the hammer with the work-engaging member.

2. A power-operated percussive tool comprising a reciprocable hammer, a Working head secured to said tool, a work-engaging member supported in said head for reciprocable movement in axial alinement with said hammer, a transversely movable block disposed within the head between the hammer and said work-engaging member, said block having an opening therethrough for permitting contact of said hammer with the work-engaging member, the forward portion of said opening being tapered, resilient means in engagement with said block and normally retaining it in position to prevent contact of the hammer with said work-engaging member, said work-engaging member being tapered at its rear end for cooperation with the opening in the block thereby t0 move the block against the tension of said resilient means and establish contact of the hammer with the workengaging member when the latter is subjected to rearward pressure.

3. A power-operated percussive tool comprising a barrel, a, hammer axially displaceable therein, meansfor reciprocating said hammer in said barrel, a hollow head secured on said barrel, a Work-engaging member carried by said head, a transversely moveable block in said head provided coaxially with an aperture and a tapered socket, said work-engaging member being provided with a tapered portion toA co-operate with said socket.

WILLIAM HENRY DEAN.

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

UNITED STATES PATENTS Gubbins Sept. 25, 1945

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