US2689496A - Jaw-locking mechanism for pipe wrenches - Google Patents

Description

Sept. 21, 1954 E. M. CHAPPELL. JR 2,689,496

JAW-LOCKING MECHANISM FOR PIPE WRENCHES Filed May 25, 1953 FIG.I

zlNVENTgiia Patented Sept. 21, 1954 UNITED STATES PATENT OFFICE JAW-LOGKING MECHANISM FOR PIPE WRENCHES Edward M. Chappell, Jr., Dana Point, Calif. Application May 25, 1953, Serial No. 357,219 1 Claim. (01. 81-100) This invention relates to pipe wrenches and more particularly to mechanism for releasing, holding, and adjustin the movable jaw of a pipe wrench.

It is characteristic of pipe wrenches that they are designed to rock with a ratchet action about a cylindrical object such as a, pipe, increasing the tightness of their grip upon such an object when moved rotatively in one direction and relaxing their grip when moved in the opposite direction. To accomplish this purpose, pipe wrenches have one jaw which is not only movable longitudinally relatively to the other law but also has limited angular movement relatively to the other jaw, the angl between the opposed jaw faces changing very slightly as the angle between the jaw shanks changes. Relative angular movement of the jaw shanks is usually provided for by having the guide passage or sleeve through which one shank slide pivoted to the handle or otherwise enabled to tilt. It is an object of this invention to provide a pipe wrench which may be set for any desired jaw-spread without the use of worm-screws to move it.

A further object of my invention is to provide a pipe wrench which may be closed to a desired jaw-spread by simply pushing one jaw relatively to the other in a closing direction, and which then will remain at the set spread-with allowance .for the previously mentioned ratchet action-until it is intentionally released, and which then may be released by finger-pressure on a simple locking device.

Still another object of my invention is to provide a pipe wrench having a locking device which itself receives very little strain but which effects a look by binding, one upon another, parts of the wrench which are necessarily strong for the purposes of the wrench and which can therefore undergo the locking strain without injury.

In the accompanying drawing, illustrative of a typical embodiment of my invention, Fig. 1 is a side view of my improved p'pe-wrench, showing the wrench clamped and locked;

Fig; 2 is a fragmentary view from the opposite side, ShOWillg the wrench unlocked;

Fig. 3 is an elevational view, drawn on an enlarged scale, of a locking plate used in my wrench; and

Fig. 4 is a perspective view, drawn on an enlarged scale, of a spring for actuating the locking plate.

Having reference to the details of the drawing, I have shown a Wrench having a handle 5, and ajaw 6 integral with the handle and generally referred to as the fixed jaw of such a wrench because it has no movement relative to the handle. A sleeve 1, also integral with the handle 5, has apassage 8 for slidingly receiving theshank 9 of a movable L-shaped jaw 19, the serrated jawface II of thejaw 10 bein opposed to the serrated jaw-face 12 on the end of thejaw 6 in planes substantially normal to the handle 5. It will be seen that the sleeve 1 is not pivoted upon the handle 5 in the manner of the well-known Stillson wrench, but permits rocking movement of the jaw Ill by virtu of having thepassage 8 tapered in the direction of angular movement of the jaw 1!] so as to closely embrace theshank 9 at the end of thepassage 8 distant from jaw face l2, and being expanded at the end of thepassage 8 adjacent the jaw-face I 2. It will seem that the jaw tends to rock upon the shoulders l3 and M at the margins of the narrower end of thepassage 8.

The sleeve 1 also has a transverse opening or passage [5 which extends into thejaw 6 and intersects thepassage 8. The passage l5 communicates with the outer surface! 6 of the sleeve 1 through an opening IT. The wall It of the passage [5 remote from the jaw-face l2 and the wall I9 of the opening I! in continuation thereof are in alignment normal to thepassage 8; theopposite wall 20 of the passage I5 is inclined so that the passage I5 widens as it enters thejaw 6, thewall 20 joining the wall 2| of the opening I! at a position slightly inwardly from the opening H but outwardly from thepassage 8. The wall 2| is normal to thepassage 8, like its opposite wall I 9, and consequently there is formed at the junction of thewalls 20 and 2| ashoulder 22, on the side of the passage [5 nearest thejaws 6 and 10.

A plurality ofplates 25, shown individually in Fig. 3 and contained as a group in the passage [5 havestems 26 which extend through the opening I! andapertures 21 arranged to be aligned with thepassage 8 and to receive theshank 9 of the jaw [0. Theapertures 21 are of suificient size in the longitudinal direction of theplates 25 to permit theshank 9 to slide freely through them when the plates are normal to the shank as shown in Fig. 2, but to cause the plates to bind upon the shank when slightly inclined at acut angles to the shank as shown in Fig. 1. Aleaf spring 28, havingopenings 29 to receive theshank 9, is mounted behind theplates 25 and urges them to assume the inclined position shown in Fig. 1.

A sufficient number ofplates 25 are used so that in combination with thespring 28 they substantially fill the opening ll. One plate of requisite thickness may be used in place of the group of plates.

Theshank 9 of the jaw in may be provided with a stud 3! which by contact with the sleeve 1 prevents the jaw ID from being entirely removed from the sleeve.

It will now be seen that the effect of theleaf spring 28 is to cause theplates 25 to pivot tilt upon theshoulder 22 and that forward pressure, towards the jaws of the wrench, upon thestems 26 will cause theplates 25 to assume the position normal to theshank 9 illustrated in Fig. 2, thespring 28 being then compressed, and that release of such pressure permits the spring to move the plates pivotally upon theshoulder 22 to the acute angle position relative to theshank 9. In the position shown in Fig. 2, the jaw H! may be moved freely in either longitudinal direction, theshank 9 sliding through thepassage 8 and through theapertures 21 of theplates 25. But in their inclined position theplates 25 bind with light pressur upon theshank 9 and tend to pivot the jaw Ill upon the marginal shoulder I3, causing theshank 9 to frictionally engage the wall of thepassage 8 remote from thejaw 6. In these circumstances thejaw 10 may be moved longitudinally only with great difficulty.

When the jaw faces II and I2 engage an object such as indicated at 3|, and the handle 5 is swung as usual in the direction of the arrow S, torque is applied to cause the jaw H] to move in the direction of the arrow T relatively to thejaw 6, this movement tightening the jaws upon the object 3|. The same movement of course tends to pivot theshank 9 upon theshoulder 13 towards the jaw 5. This pivotal movement of theshank 9 tends to increase the relative inclination of theshank 9 andplates 25, but this inclination is already at the permitted maximum. The plates will slide upon thspring 28 and on thefulcrum shoulder 22, to follow theshank 9, but will bind ever more tightly upon theshank 9 and increase the pressure of the shank against the passage margin [4.

The jaw ill is now held firmly against longitudinal movement but will relax its grip upon the object 3! the instant that torque upon the handle 5 is reversed.

To release the wrench entirely from the object 7 31, thestems 26 are pushed toward the wrench head to bring theplates 25 normal to theshank 9.

Practically no torque or bending strain is applied to theplates 25, the strain upon them being largely longitudinal, and such bending strain as occurs takes place at the area in contact with thefulcrum shoulder 22 where the plates have the greatest unbroken width and strength between thestems 26 and theapertures 21. The forces which hold the jaw ID are appliedthrough theplates 25 in small part to thefulcrum shoulder 22 and in large part first to the shoulder l3 at the narrow end of thepassage 8 and then to the opposite shoulder H3. The further the jaw I0 is extended relatively to the jaw 6and then, not infrequently, the greater power is required to turn a larger objectthe greater the binding pressure upon the shoulder Hi becomes, the object 3| then becoming the moving force, the shoulder l4 being the fulcrum, and the resistance of theplates 25 to longitudinal extension of theapertures 21 being the resistance of a leverage system.

Iclaim:

A wrench comprising: a fixed jaw; a handle integral with said fixed jaw; a movable jaw; said jaws having jaw faces opposed in planes substantially normal to said handle; a shank on said 1 movable jaw substantially normal to the jawface thereof; a sleeve on said fixed jaw having a first passage for slidingly engaging said shank; said passage having marginal shoulders closely embracing said shank at the end of said passage distant from said jaws and being expanded at its opposite end to permit rocking movement of said shank within said passage upon said marginal shoulders as fulcrums; said sleeve having a second passage intersecting said first passage and having a shoulder within said second passage disposed outwardly from said first passage and on the side of said second passag toward said jaws; a plate contained in said second passage having an aperture aligned with said first passage through which said shank may slide when said plate lies perpendicular to a longitudinal axis of said shank and being tiltable about said last mentioned shoulder to lie at an angle with respect to said axis of said shank so that margins of said aperture bind upon said shank, the angle of tilt increasin when said shank is.rocked so as to bring said jaws closer together; and means resiliently urging said plate to assume said tilted angle.

References Cited in the file of this patent UNITED STATES PATENTS

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