US2391143A - Wrench - Google Patents

Description

Dec. 18, 1945. A. ERTNER 2,391,143

WRENCH Filed Oct. 2, 1943 inventor August C. E'rtner Gttomeg V cientand convenient tool.

Patented Dec. 18, 1945 {f /UNITED STATES, PATENT: OFFICE WRENCH August 0. Ertner, Seattle, Wash., assignor to Fed- ,eral Trading 00., Seattle, Wash.,=a partnership composed .Thorn I of August 0. Ertner and J. Frank Application October 2, 1943Q'SerialNo.504,727

2 Claims. (01; 31 -152) My invention relates to a quick adjustable wrench, and more specifically to the particular type of jaw holding mechanism employed. 'While my wrench jaw holding mechanism may beincorporated in wrenches of different types, in 'any'fsuchinstallation the user may merely push the movable jaw towards the fixed jaw, thus to grip the work between them, without 'di frectly manipulating the jaw holding mechanism,

The movable jaw will be held automatically in such work gripping position against great force tending to separate the jaws. Despite ability of thejaw latch to resist displacement of the movable jaw under working load such jaw can be released by a simple manual operation for movement away 'from thefixed jaw.

f It is therefore anobject of my invention to provide jaw latching mechanism which will be moved automatically into holding position whateverthespacing between the jaws maybe, so that it 'will'be'in condition at all times to resist movement of 'th'e movable jaw away from the fixedfjaw by a force'reacting between them; Nevertheless the movable jaw may be quickly retracted at will from the fixed jaw, and over'any distance, by manually releasing the latch mechanism.

"More specifically it is an object to provide a latch construction capable of afiording such operationwithout being. injured by a heavy load which can be withstood by the other wrench parts, and without slippage of the movablejaw 1 upon initialapplication of the load. The latch ing mechanism is therefore positiv and self-act An additional object is to provide a latching wrench having such capabilities but composed of few parts, which; can be produced by simple machine operations, and which can be assembled readily to afford an economical, yet an effi- LOtherobjects of my invention which result fromthe'particular nature and characteristics of the mechanism-which I prefer will'be understood from I the following detailed description of a wrench construction typical of my invention. It will be understood that the: wrench shown in the drawing is only representative, being one type in which my latch'can be used, and various' details of the latch construction can be altered as desired while embodying the important features defined more particularly in the appended claims.

LFigure- 1 is a top perspective view. of a wrench embodying my latch, with parts broken away to reveal the latch structure.

Figure 2 is a side elevation view of the wrench head, with part of the casing broken away to expose internal structure, and Figure Bis a rear elevational view of the wrench head.

Figure 4 is a plan'view of a latch plate removed from the wrench. Figure 5 is a perspective view of one type of latch spring which may be employed. 7

As a typical embodiment of my invention I have illustrated in the drawing a monkey wrench includinga fixed jaw l' integral with a rectan' gular shank I0, which shank projects through an aperture 20 in a movable jaw 2, guided by the shank for reciprocation toward and away from the fixed jaw I. The end of the shank remote from the fixed jaw forms the handle. It will be understood that the particular shape of the jaws I and 2, the manner in which the jaw I is mounted on its shank l0, and the angular relationship of the 'jaws to the shank are matters of choice,- and may be varied according to the particular type of wrench embodying my latch mechani'sm, and the use for which the wrench is intended. The latch construction described below is interengaged between the movable jaw 2 and the shank Ill, irrespective of th particu-' lar jaw structure features and the extent of movement of jaw 2 along the shank l0.

'The latch construction, to which my invention particularly relates, is enclosed within a case 3, preferably 'made of sheet metal, which may be secured to the lower portion of the movable jaw '2 in any suitable manner, such as by a screw 30. It will be understood that the aperture in the bottom of this casing through which the shank l0 projects, and the hole 20 in the movable jaw itself, are of a size to afford sufficient clearance for the shank to slide easily" through them without binding. Neither the movable jaw' nor the case is relied upon to assist in gripping: the shank'for the purpose of holding the r'novable jaw from sliding along the shank.-

The latch mechanism proper consists of a p1urality of thin plates-3|, at least two in number, each having a body portion of a size approach ing the inner cross section of the casing 3.

for example the shank may project through a of the plate length appreciably exceeding the width of the shank parallel to the jaws l and 2,

. so that such plates maytilt at a substantial an-E Each latch plate embraces shank l0 somewhat loosely},

gle relative to the shank. Moreover aperture 32 is preferably located considerably nearer one end of the plate 3| than the other, to form a tongue projecting transversely of the wrench shank for a substantial distance beneath movable jaw 2. The tongue of the upper plate 3| abuts the bottom of a shoulder 2| projecting froina portion of jaw 2 lremote 'fromthawrench shank '10 down ward well below the portion thereof through which the shank passes. Such shoulder is inclined relative to the shank so that its portion most remote from the shank projects farthest downward, as will be discussed more fully hereafter.

Because aperture 32 in eachplate 3| *is longer than the corresponding transverse dimension "of the wrench shank, each latch plate may tilt through a substantial angle relativeto'theshank Asthe force :is applied the'sliding jaw will tend to move away from the'fixed jaw, that is downward in Figure 2, and the jaw shoulder --2! will press against theouter endof the tongue of the upper'latch plate 3| at a location substantially beneath the center of the gripping-partof jaw 2 projecting beyond shank l0. Such-pressure will tilt ithe'upperlatch plate-bytheleverage thus ex-' erted,.and in succession eachlatch-plate beneath it,.in a direction so that the lower corner of the aperture edgeinext to thetongue and the upper corner of the aperture edge remote from the tongue-will ibitesimultaneously against the shank.

Assumingthat the apertures 32 in all .the overlapping latch plates-:3! are of the same length, the corresponding corners of all the apertures will thus bite "similarly against shank I0 simultaneously,cas-shown in Figure .2. Even though the latch plates mayberather thinrand may tend to be bent *by the force *exerted on-their tonguesby the jaw shoulder, any deflection whichoccurs will act to increase thegripping effect of each plate upon=the shank. No individual latch plate can be deformed beyond its-elastic limit, however, because each plate in turn-supports the one above it, and all ftherefore actin concert to withstand thestressexerted on them by pressure of .thejaw shoulder 2 I.

It'isto .be noted particularly how'the pressure of thejjaw shoulder'against-the tongue of the upper'latch plate is transmitted successively' toeach of the underlying latch plates. All these latch plates abut contiguously, and preferably the holes 32 of all the plates are of precisely :the same length. If there is any variation in the length of .such holesthe hole in each underlying plate should not exceed the length of the hole in the platenext above it. Only where the plates are of :su'hiciently thin :stock '130 be somewhatyieldabl lunder'loads usually to beexpected, a-slight variation may not be too detrimental. In that event, 'the'plates all being in contiguous face-toface "engagement, the tongue of each under plate would bendslightly before the plate next wabove itwould grip the shank.

In order to insure substantially immediate'gri ping xofiall the latch plates against shank [0 a spring 33, encircling the shank-is interposed-between the bottom of the'cas '3 'andithe aperture'd end 0f the lower latch plate. The specific shape ofzsuch spring is not .ofli'great importance, :but

that shown in Figure 5 has been found to be effective and is very compact. This spring, of the compression type, acts against the apertured ends of the latch plates in a direction toward fixed jaw I to tilt the latch plates about shoulder 2! as a fulcrum, that is, in the same direction as pressure by the jaw shoulder tends to tilt the plates relative to shank "HI. Thus :upon application of a force reacting between the jaws the latch plates will merely be forced more tightly "against the shank, already being located properly lengthwise of the shank to exert the requisite holding action. The only separating movement --of 'the' jaws which can occur under load, there- "fore, .is that'corresponding to the deflection of the tongues 'ofthaplates.

In order to exert the maximum leverage action-on thellatch, plates for their length it is desirable that the jaw shoulder 2| engage the tongue of the upper plate at a considerable distance fromtsh-ank ll]. Anticipating the possibility of some slight deflection of the latch plates under heavy load,-the lower end-of the jaw shoulderis preferably inclined relative to shank H1 :at fan angle somewhat greater than the maximum Y angle-at rwhich the latch platetongues can be tilted when the plates are in gripping attitude. The shoulder thus engages the uppenplate tongue at all timessubstantially along a [line immediately below the central portion of the part of jaw 2 projecting beyond shank NJ, to leave clearance between such tongue and theportion of the jaw shoulder-nearer .shank 10 under all loading conditions.

Sincetilting of'the-latchplates 3| to decrease the angle between them-and shank 10 accomplishes a gripping action to restrainsliding of the movable jaw along the shank, it will be-evident that thelatchrplates may be released from the shank, to --enable themovablejawto be slid along .it, hy-tilting them in the=opposite direction. Such movement increases the angle between the latch plates and the shank, moving them intoa position more nearly perpendicularto the shank so that clearance isaffordedbetween the latch plateapertures and the shank.

Such latch releasing tilt of the latch plates maybe accomplished positively by engagement of the operatorsthumb with a tab 34 projecting from the end of the upper latchplatelil opposite the latch plate tongue. .As shown in Figures 2 and3, 'thistab projects through a slot in the back of the casing, so that itmay be engaged readily. Preferably all the plates have'such tabs, sothat the releasing pressure is transmitted'from one plate to the next at a location reasonably far from the slide. It is not necessary, however, that more than'the uppermost 'plate have such a'tab. If the lowermostplate also has a similar tab 3-4, however, itmay serve as -a seat for a'rearwardly projecting loop of spring "33; as shown.

The operation of mywrench will be-readily apparent. The movable jaw may'simply-be pushed toward the fixed jaw, during which operation the l'atchplates will slide along the shank, since there is no load on them. In fact, if thetongue of the lower :latchplate is engaged zby the case 3,:the plates would all be tilted positively toward released position, mzorenearly perpendicularto the shank. Nevertheless"whenever the :movable jaw comes to rest'spring 3-3 will'immediately push the latch plates away from the bottom of the case, so that the'tongue'of the upper'latchplate will be pressed against shoulder 2|, and ?.the i-plates will she tilted :substantially :into .;shank gripping latch plate tab 34.

shoulder 2| on the latch plate tongues is considposition. When the load is applied on the wrench, therefore, creating a force tending to separate the jaws, the pressure of shoulder 2| on the upper latch plate, transmitted in turn to the underlying latch plate, will tend to tilt them relative to shank H1 in a direction to grip it tightly.

Because the latch plates are in contiguous face-to-face contact, each one supports the other over substantially its entire area to aflord an intimate, distributed supporting action. Even though each plate is made of material so thin that the force exerted by jaw shoulder 2| would readily bend it, if used alone, the stacked arrangement of the latch plates, in which they act conjointly, will prevent deflection of any plate to an extent which would result in its permanent deformation or breakage. Furthermore, while a single latch plate would not afford sufiicient gripping action because only two corners would be pressed against the shank, where a plurality of latch plates are provided two corners of each exert a gripping force, so that even with two plates a satisfactory holding action is effected, which a single latch plate will not produce. Each additional plate will add two more gripping edges, but two or three plates will usually afiiord all the holding action necessary.

As long as any substantial load is applied between the jaws the latch plates will be pressed against the shank too tightly for them to be released even by pressure of the thumb on the upper The leverage of the jaw erably greater than that afforded by pressure on the plate tabs. The gripping action of the latch plates therefore cannot be inadvertently released, even if the wrench is being manipulated by two hands.

When pressure on the movable jaw is relieved, however, pressure on the latch plate tabs 34 will tilt the plates readily into released position, be-

cause of the considerable leverage offered by such tabs. The movable jaw may then be slid readily away from or toward the fixed jaw to any extent desired. Although it is not necessary in most instances to apply manual pressureto the latch plate tabs in order to release the plates positively for closing movement of the jaws, such reciprocation may be facilitated in some instances by such manipulation, especially immediately after the wrench has been subjected to an unusually great load which tends to set the latch plates tightly against the shank.

It will be seen, therefore, that with my latch construction the wrench may :be operated readily for either opening or closing movement of the jaws by one hand, and the desired jaw movement may be accomplished very quickly. Despite such case of adjustment'the provision of a plurality of contiguously engaged latch plates produces an immediate and sufliciently powerful gripping actionto prevent any appreciable slippage of the movable jaw upon application of a load or thereafter, however great such load may be within the capacity of the wrench as a whole.

I claim as my invention:

1. A wrench comprising a fixed jaw, a shank integral with said fixed jaw and projecting generally transversely therefrom, a movable jaw slidable on said shankand having a shoulder projecting from the side thereof opposite said fixed jaw and located remote from said shank, the end of said shoulder being inclined toward said shank and fixed jaw, and'a plurality of thin latch plates disposed in contiguous face-to-face contact, apertured to embrace said shank and engaging said movable jaw shoulder, being tiltable by pressure of said shoulder thereon, by a force acting to separate said jaws, into pinching engagement with said shank at an angle relative "thereto slightly greater than the angle of inclination of said shoulder end relative to said shank, to preserve line contact between said plate and the side of said jaw shoulder farthest from said shank under usual loads, thereby restraining sliding of said movable jaw along said shank away from said fixed jaw, said latch plate being en- "gageable with an appreciable area of said fixed jaw shoulder upon bending under excessive loads,

such engagement limiting the degree of possible bending of said plate.

2. A wrench comprising a fixed jaw, a substantially rectangular shank integral with said fixed jaw and projecting generally transversely therefrom, a movable jaw slidable on said shank and having a shoulder projecting from the side thereof opposite said fixed jaw and located approximately at the center of its gripping part projecting from said shank, the end of said shoulder bein inclined toward said shank and fixed jaw, a plurality of thin latch plates disposed in contiguous face-to-face contact and having a substantially rectangular aperture therein to embrace said shank, each having a tongue projecting a substantial distance transversely from said shank to a location beneath said movable jaw shoulder, the tongue of th latch plate next to said movable jaw engaging said movable jaw shoulder, said latch plates being tiltable conjointly by pressure of said shoulder on'the latch plate tongue engaged thereby, by a force acting to separate said jaws, through a substantial angle into pinching en agement with said shank at an angle relative thereto greater than the angle of inclination of said shoulder end relative to said shank, to preserve contact between said plate and the side of said jaw shoulder farthest from said shank along a line perpendicular to the movable'jaw and substantially directly beneath the center of its gripping part, thereby to restrain sliding of said movable jaw along said shank

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