US2542241A

US2542241A - Ratchet mechanism

Info

Publication number: US2542241A
Application number: US705031A
Authority: US
Inventors: John A Fors
Original assignee: New Britain Machine Co
Current assignee: New Britain Machine Co
Priority date: 1946-10-23
Filing date: 1946-10-23
Publication date: 1951-02-20
Anticipated expiration: 1968-02-20

Description

Feb. 20, 1951 J. A. FoRs RATCHET MECHANISM Filed 00's. 25, 1946 :11... RN mw 9m,

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/ INVENTOR v" 'dJ-. FaQ/d BY '-7 M AUORNEYS Patented Feb. 20, 1951 RATCHET MECHANISM `lohn A. Fors, New Britain. Conn., assignor to The New Britain Machine Company, New Britain, Conn., a corporation of Connecticut Application October 23, 1946, Serial No. 705,031

My invention relates to ratcheting devices and in particular to a reversible or two-way-engaging ratchet Wrench.

It is an object of my invention to provide an improved ratchet-wrench construction.

It is another object to provide an improved ratchet mechanism the parts of which lend themselves to simple and inexpensive fabrication.

It is a more specific object to provide an improved shift means for a pivot pawl in a ratcheting device of the character indicated.

Other objects and various further features of the invention will be pointed out or will occur to those skilled in the art from a reading of the following specifcation in conjunction with the accompanying drawings.` In said drawings:

Fig. 1 is a plan view of a ratchet wrench incorporating features of the invention;

Fig. 2 is a fragmentary view similar to Fig. 1, but with a covering element removed;

Fig. 3 is a fragmentary elevational View of the head of the ratchet of Fig. 1 with parts of the casing broken away to illustrate the cooperating relationship of parts;

Fig. 4 is a fragmentary vertical sectional View tak-en substantially in the plane 4 4 of Fig. 1; and

Fig. 5 is an enlarged exploded perspective view 'illustrating the cooperation between two elements of the ratchet of Fig. 1.

Broadly speaking, an important part of my invention contemplates an improved mechanism for pivotally shifting the pawl in a reversible ratcheting device in which the pawl is supported within a chamber including a surface cylindrical about the pivotal axis of the pawl. The pawlshifting means includes an arcuate surface slidingly engageable within the cylindrical surface and it also has a part engageable with the pawl. In the specific form to be described, the pawl has a chordlike at or abutment surface for cooperative engagement with a correspondingly fiat and substantially coextensive surface on the shift means.

Referring ,to the drawings, my invention is shown in application to a reversible ratchet wrench having a shank or handle portion I0 and a head II. Pivotally supported within the head II is a ratchet member I2 anda reversible pawl I3 having duplicate sets of ratchet-engaging teeth I4-I5. One of the members I2-I3 is a driving member and the other is a driven member, and in the form shown the ratchet Wheel I2 is driven Aby the pawl I3. The direction of drive may be selected by selectably positioning one or the otherfof sets of teeth I4--I5 in engagement 8 Claims. (Cl. 19h-43)` with the ratchet wheel I2, as by rocking the pawl I3 about its pivotal axis. The parts which have thus far been described are well known and form no part of my invention.

According to the invention, I provide novel means for selectably positioning the pivotal pawl I3 for reversing the direction of the ratcheting operation. This means contemplates an additional member which may include a shift lever I6. Integrally formed with the shift lever IB is an enlarged or head portion I'I, characterized on one side by a generallyarcuate surface I8 .which may slidingly abut a correspondingly arcuate surface or bore I9. It will be understood that, although this sliding abutment is circumferentially continuous for the full arcuate extent of the head of lever I6, there may be some unsupported upper areas of the arcuate surface I8 immediately adjacent the juncture of lever I6 with head I 1; however, the unsupported areas may not impair the eiectiveness of full arcuate support of the lever head I1, as will be clear. The other side of the shift head I'I is formed for engagement with a portion of the shiftable pawl I3. In the form shown, this cooperative engagement between the pawl I8 and the shift mechanism comprises a generally chordwise extending surface 20 on the pawl I3 and a substantially coextensive similar surface on the shift head I 1. It will be clear that, when the pawl I3 is pivotally held within the head I I and when the shift head I'I is inserted between the flat 20 and the cylindrical bore I9, there is formed a sufficiently positive engagement between the shift leverI' and the pawl I3, so that a rotary displacement of the shift lever I5 will result in a rocking of both the pawl I3 and the lever IB about the pivotal axis of the pawl I3, whereby ratchetingV action may be reversed as desired.

In accordance ,with the invention, I provide novel means for readily assembling and holding together the parts which have been described. In the form shown, the pawl I3 is formed with' generally opposed arcuate outer surfaces 2I-22 which during a reversing shift may slide freely over the cylindrical wall of a bore within the head; II. As shown'this bore coincides with the bore I9' which receives a part of the shift head Il. The ratchet wheel I2' is likewise received within' counterbore 24 in the head II, and one end` thereof may be journalled as at' 25 within a bore in the head II. The bores 24 and t9 may be saidV to be intersecting and to enter the head I I from` opposite sides of the head I I. The other end of the ratchet wheel I2 maybe freely, pivotl through a part of the head H through the pavl'ly I3 and threadedly engageable with a pawlcovcr plate 30, which in turn may be flush-mounted second of said angular positions, said shifting means including a shift member having an arcuate surface to t said bore and a portion axially slidingly engageable with a part of said pawl oi the pivotal axis of said pawl, and removable cover means supporting one end of said pawl member and serving to retain said pawl member 'said lshift member in non-sliding engagement with each other.

v2. In a ratcheting device of the character indicated, a head, a pawl member pivotally sup- -f ported Within a cylindrical bore in said head and in the head Il as by seating ina counterbore The cover plate 3i? preferably includes a shanls portion 32 which may slidingly nt within a bore 33 in the pawl i 3.

In use, the direction of ratcheting may be maintained as selected, by the action of a's'pringldetent mechanism 33 upon one side or theI other ofya radially Ventend-ing camming proiection formed in the pawl S3. During ratcheting, the pawl rocks about its pivot, with thev arcuate surfaces 2I-22 sliding freely 'past adjacent areas of the bore i9. However, under 'load there is a direct transmission of thrust from the r tchat-n engaging teeth, across the pawl, and to the head Il'by a vfirm abutment of Say the arcuate suriace'Zi with the adjacent area of the bore it, as will be clear.

1It will Vbe appreciated that I lhave described an lnilvroved ratchet-wrench construction in which the cooperating parts lend themselves to simple and inexpensive fabrication. In particular, the means forv Shitinathe pivot pawl il@ reversepr modify the ratcheting function represents a novel improvement over the art.

"Mywproved pawl and shifter construction utilizes parts that vare relatively easy t0 Construct, and, vvvhile they are so combined into the Wrench or handle head il, as to present a oompletely flush surface with no snagging projections, these parte may be readily disassembled, as for cleaning. It will be understood that machining of 'the pawl member i3 may be of the simplest, said member I3 being formed from bar stock with `a minimum of Waste, with the various teeth I4-i5 and shoulders and other recesses being milled; the shift-lever unit il may be a simple die casting. Not even vthe upturned end ofthe shiftelever handle i5 yneed proect above the iiush top of the wrench head, and a mere loosen inggofthe simple bolt 2S will suiice for disassennA bly ci vthe Apavvl andpavvl-shift mechanism, as for cleaning. It Will be noted that the novel pawl construction, -vvhereby pavvl journalskor bearings are completely closeol'to the outside, may materially improve the resistance oi the mechanism to grit and grime-thus reducing the need for frequent cleaning. f

`While have described the invention for the preierredk form shown, it will be understood that modifications may be made within the scope of the invention as dened in the claims which iol- 170W- 'I claim:

1. In a ratchet device vof the character :ndi-

cated, a head, a pawl member'pivota'lly sup# ported in a cylindrical bore in said head. a ratchet member pivotally supported in said head, said pawl `member being variously engageable with saidfratchet member for various angular posi-l tions of said pawl member with respect to ratchetmember, shifting means engageable with said pawl for shifting the same from a iirst to a having substantially diametrically opposite shoulder port-ions 4in adjacency toV said bore, and a shift member having a generally arcuate surtace slidingly tc'iit said bore and including chord,-

-cvise-projecting jpor-tions engageable with said opposed shoulder portions of said pawl member.

3. In a ratcheting device of the character indicated, a head, a pawl member pivotally supported in a cylindrical bore in said head; a ratchet member pivctally supported insaidhead and engageable with said pawl member, one fof said Amembers being` a driving element and the other of said members being `a driven element; raid pawl member including generally arcuate surfaces in adjacency to substantially diamet-g rically opposed portions of said bore, a substan-` tiaily chordvvise extending Ashoulder on saidpaivl member `between said arcuate surfaces, and -a shift member having an'arcuate surface sliding'- ly to saidbore and including a projecting portion eneageable with said shoulder, said head in'- cludi-ng a cover'portion over apart of said shift member .for vretaining said shiftmember in en# gagement with said pawl member.v o

in a ratcheting device vof the'characten indicated, a heada pawl member pivotally supported in a cylindrical bore .in saidhead, said pawl member including duplicate ratchet-en-A gaging means .symmetrically disposed about a glane of symmetry passing through the pivotal axis of said pawl member, a generally chordtvise extending shoulder symmetricallyv cut with re-f spect'to Vsaid plane of symmetry, and a shift member including means engaging said shoulder and slidably fitting said bore, said head including cover means covering both ends of said pawl member and a partof saidshift member, with a part of said shift member projecting out from under said cover means for finger engagement.v

'5. In a ratcheting device ofthe character ine dicated, a head, a pawl member pivotally sup ported in `a cylindrical bore'in said head, saidl pawl member including duplicate ratchet enr gag/'ing means oppositely disposed about a plane, of symmetry including the pivotal axisof said pawl member, a substantially flat abutment sur', face on saidv pawl member, said iiatsurface 'de-g scribing a chord with respectfto said vpivotal axis, and a shift lever including an arcuatexsurA face slidably engageable with said bore Yandza flat surface substantially coextensive with said chord,l said head including cover means ush therewith and extending over'said pawl member and'over a part of said shift member, With an-V other part of said shiftmember projecting 'out `cover means for ringer -engagetrom under said ment. 6. In a ratcheting device Vof the character'ine dicated, a head, a: pawl member pivotally sup# ported in a cylindrical bore in said hea'dysaid: pawl member having duplicate sets of ratchetel engaging means for selectable ,use in a two-way. engaging device,` springdetent `means :cooper-f ating between said pawl and said head for retaining said pawl member in a selected position for one of said two-way engagements, a chordlike abutment surface on said pawl member, and a shift lever including an arcuate surface slidingly engageable with said bore and a flat surface engageable with said abutment surface, said head including cover means iiush with said head and extending over said pawl member and over a part of said shift member.

7. In a ratchet wrench, a head, a cylindrical ratchet bore extending into said head from one side, a cylindrical pawl bore extending into said head from the opposite side, said two bores intersecting each other, a ratchet member in said ratchet bore and having a wrench-attaching part extending to the outside of said head, a retaining washer extending over said Wrench-engaging portion and secured to said head for holding said ratchet member in place, a pawl in said pawl bore, a disc for closing the outer end of said pawl bore, means extendingr into said head and disc and passing through said pawl for holding said disc in place and connng said pawl in its bore, and shift means for said pawl engageable at the outside of said head, said shift means projecting out from under said disc, whereby the finger-engageable part of said shift means may not project above the otherwise smooth and ilush surface of said head.

8. In a ratcheting device of the character indicated, a ratchet head having a bore, a shiftable pawl with an arcuate surface to fit said bore, covering means carried by said head for covering both ends of said pawl and for providing central bearing support therefor, the cover means on one end of said pawl being removable for axially sliding removal of said pawl, said head at one side thereof having an arcuate open portion between the main body of said head and said cover means, and. shift means engaged with said nawl and projecting out from under said cover means through said opening.

JOHN A. FORS.

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

UNITED STATES PATENTS Number Name Date 1,868,839 McNaught et al. July 26, 1932 1,888,885 Pepperdine Nov. 22, 1932 1,957,462 Kress May 8, 1934