US2448095A - Signal type torque indicating wrench - Google Patents

Description

Aug. 31, 1948. E. G. HALLETT ETAL 2,448,095

SIGNALv TYPE TORQUE INDICATING WRENCH Filed Jan. 4, 1945 .E 7 i SETTER' A PROJECTION a POSITION c n I121) err/tors .4. C. EDOLUZ'Z/ Heal, Labia Patented Aug. 31, 1948 SIGNALTYPE TORQUE INDICATING WRENCH Ernest GeorgeHallett, West. Footscray,nand Andrew CanfieldBrown, Fo'otscray, Victoria-,,.Aus-

tralia.

Application January 4, 1945, Serial No. 571-;296 In Australia January 19, 1944 (aim-52.5)

Claims. I

This invention relates to improvements in and connected with tension wrenches and the likethat is to say, -wrenohes of the character which enable a predeterminedtension to be imparted to a part engaged thereby or to interengaging screw-threaded parts .or the like.

S'everal'types of tension wrenchesare'already known,.the majority of such wrenches being. calibrated to indicate the torque imparted to the part engaged thereby such as a nut. or bolt head, though some types are not calibrated and. are used in conjunction with comparators or master setters. a I Several known types of tension wrenches depend for. their operation upon the deflection of the operatinglever arm relatively to a fixed point or coacting, abutment and one such type of wrench incorporates a. depressible plunger mounted in a fixed. abutment arm. and arranged to. coact with awedge-s'haped contact block which isslidably mounted'on a graduated. portion ofthe operating lever adjacent to the handle of the latter. When the lever arm is deflected sufliciently to cause theplunger tobe. depressed to a predetermined extent,,it releases a spring pressed trip. pin whichthen projects from the abutment arm and visually indicates that the predetermined torque (the value of whichv is. designated by. the scale) has. been-applied. The release of the. trip pin is accompaniedby a. clicking noise which provides an audible and visible signal also.

In certain-other types. of; tension Wrenches, the pressure is transmitted from the operating lever to; the nut or the like through the medium of a member-e. g. a plunger which is depressible in opposition to an adjustable spring whereby the plunger is depressed when the predetermined torque has been applied.

Several other types of tension wrenches, which operate in': somewhat different ways but; which employ'closely related. principles,.are also known and used. All of the wrenches of the aforesaid character known to us, however, are provided at one-end of an operating lever with a head adapted to receive the stem of a box wrench, .whereby the axis of the nut or other workpiece is coincident with the axis of the head and this. common feature. involves several disadvantages. In the first place the rangeof sizes of. box wrenchesor adapters. which may. be used is limited so that generally it is necessary to employ a number of Wrenches of different. sizesto suit even commonsizes of nuts and bolts. j v

Furthermore, the boxtype of wrench is not alwaysconvenient to'use, apart from the fact that a box wrenchof the required size? is not always available.

Finally-the range of. torques capable of bein indicated by tension wrenches of known types is very limited, which again necessitates the provision of'a range of wrenches to meet common requirements.

Nowthe general object of this invention isto provide improvements in wrenches of the abovementioned character while a more-specific object is to obviate the aforesaid disadvantages. Still another object is to provide meanslforensuring that manual pressure is imparted to the operating lever at substantially a predetermined" position.

Accordingly one broad-feature of theinvention resides in a tension wrench or the like incorporating means for detachably connecting thereto spanners, monkey wrenches or other part engaging members of difi'erent types and sizes.

Preferablythe' part engaging'memb'er is adjustable lengthwise of'the' tension Wrench in order that the range of torques capable of being-indicatedtherebyis increased and for'this'purpose a plurality of calibration scales corresponding to different positionszof'the nut axis relatively to the adjacent end of the operating lever ispreferably provided.

Preferably setting means are provided to enable the position of said nut axis to be accurat'ely determined.

Another feature of the invention resides in providing the handle of the operating lever with a grip'ofsuch form as to ensure that it isheld'substantially at a predetermined position.

In thedrawings:

Figure 1' isa View in side, elevation of a tension wrench incorporating the preferred form of the invention.

Figure 2 is aview in plan of the tension wrench shown in. Figurel.

Figure 3 is a. fragmentary plan view and shows certain parts of the wrenchin section.

Figure 4 is a cross-sectionalview taken on the line 4-4= of. Figure 2.

Figure. 5-is a cross-sectional. view taken on the line 5'.5.of Figure 2.

Figure 6 is a view in inverted plan of the head of the wrench.

Figure 7 is. a view in plan of the head of the device and shows. a boxv wrench adjustably clamped thereto.

Figure 8 is a view'in plan of an. adjustable set.- ting device, the adjustable member thereof being shownin-section.

The" tension wrench shown in. Figures 1 to 6 of the drawings includes a resilient, operating lever I comprising a straight metal rod having a retaining head II for a part engaging tool secured to one end thereof, while a hand grip I2 is secured concentrically to the opposite end of the lever ID.

The hand grip I2 is formed with a plurality of longitudinally spaced circumferential grooves which are separated by narrow circumferential ridges I3 the form and spacing of the grooves being such as to constitute four finger grips which ensure that the hand grip is held substantially at a predetermined position.

The retaining head I I consists of a metal block preferably formed of steel and provided at one side with an integral flange I4, the inner face I of which is undercut and extends substantially longitudinally but at a small angle to the axis of the operating lever I0. Thus, when viewed in cross section as shown at Figure 4, the retaining head is substantially of angle shape but the inner face of the integral flange of the angle section is undercut. The axis of the operating lever I0 extends through the said integral flange of the head so that the inner face of the body of the head is disposed Wholly to one side of the said axis.

A hook bolt H is arranged transversely in the said retaining headi. e., at right angles to the integral flange I4 and is slidable but not rotatable therein and the hook II at one end of this bolt is disposed in opposition to the undercut inner face I5 of the integral flange on the head. The inner face ll of this hook also is undercut as clearly shown in Figure 4.

The opposite end of the hook bolt 11 is screwthreaded and projects through the flanged side of the head I I and is fitted with a suitable nut I8.

As the gap between the hook I1 and the coacting fixed undercut flange I4 is in the form of an open-ended dove-tail slot or socket of adjustable width, a spanner, monkey wrench or like tool may be securely clamped to the head with the nut engaging end or other corresponding portion thereof arranged somewhat to one side of an extended portion of the axis of the operating lever.

Thus Figure 7 shows abox wrench I9 secured to the head I I, the arm of the wrench being also shown in broken lines in Figure 4.

Alternatively any other suitable form of adjustable clamping of retaining head may be employed and such clamping or retaining head may be designed to suit right and/or left-hand wrenches. The wrench illustrated in Figures 1 to 6 is merely inverted for the purpose of tightening nuts with left-hand threads.

A metal calibration block of rectangular form is secured to an outer portion of. the operating lever I0 inwardly of the hand grip and a Wedge member 2| is slidable longitudinally thereon. This wedge member is of angle shape in cross section to embrace one corner of the calibrated block and one flange 2 I thereof is formed with a longitudinal slot 22 through which passes a fixing screw 23 fitted to the corresponding side of the calibration block.

The other flange 2I of the wedge member exzero setting by means of a grub screw 25 and this pointer moves over graduations 26 on the upper face of the calibration block, such graduations being calibrated to designate torque in foot pounds or other desired units.

In the illustrated embodiment three scales of graduations 26 are provided side by side on the upper face of the block 20 and each of these scales, which are distinguished by the letters A, B and 0, corresponds to a particular position of the spanner head or other nut engaging means relatively to the retaining head II as hereinafter explained.

An abutment arm 21 is secured at one end to the upper face of theretaining head and initially extends longitudinally therefrom towards the hand grip, the outer or free end portion of this abutment however being arranged substantially parallel and in opposition to the edge of the inclined flange 2 I of the slidable wedge memher.

A spring loaded plunger 28 projects fromthe inner face of this abutment arm and the pointed free end thereof is normally disposed clear of the said wedge as shown in Figures 2, 3 and 5. This plunger coacts with a spring loaded trip pin 29 which is slidable longitudinally within the abutment arm and normally projects somewhat therefrom as shown in Figures 2 and 3.

For this purpose the inner portion of the trip pin is somewhat enlarged in diameter to form an annular shoulder, while the reduced outer portion of the trip pin extends eccentrically through a transverse hole in the plunger, said hole being somewhat greater in diameter than tends partly across the upper face of the calibration block 20 and the free outer edge thereof is straight and is disposed at a small angle to the axis of the operating lever, the maximum width of the flange being at the outer end thereof. The outer end of the inclined flange 21 is fitted with a pointer 24 which is adjustable for the enlarged inner end of the trip end. Thus the trip pin is normally retained in its retracted position by the engagement of the shoulder thereon with the adjacent side of the plunger.

Accordingly, when the plunger 28 is depressed to a sufficient, extent, the trip pin 29 is released and is further projected until the said shoulder thereon abuts against a retaining screw 30. Thus a visual signal is given When the plunger 28 is depressed while additionally the clicking noise which accompanies the projection of the trip pin provides an audible signal. This part of the apparatus is, however, already known and doesnot by itself constitute a ,part of the present invention.

It will be evident that the torque applied by means of the Wrench is the product of the force applied to the handgrip and the distance between the point of application of such force and the axis of the nut, bolt head or the like to (which the torque is applied. Thus the values designated on the aforesaid scales 2B correspond to particular distances between the end of the retaining head II and the axis of the head of the spanner I9 or equivalent device detachably connected thereto. Y

For this purpose a setting device (see Figure 8) is preferably provided, to enable this overhand distance to be accurately determined.

This setting device comprises a straight rod 3| provided at one end with a sawcut, whereby the same may contract to enter and frictionally engage the surface of a hole 32 formed in the outer end of the retaining head II (see Figure 7), the relevant end of the rod being provided with a shoulder 33 which abuts against the said head. Alternatively, the hole 32 and the coacting-end of the setting rod may be screw-threaded.

A laterally extending pointer 34 is slidably mounted on the rod and means are provi-ded'for retaining the s'ame in any prdetermined positiori thereont as-showmthe pointer enclo'ses 8*- spnng pressed ball '35 engageable witn any one of a: plurality of longitudinally spaced circumferential grooves 36- in the rod, eachsiichgroove corresponding to-one on" the scales 2 6 on the calibration blocki-- Accordingly in the illustrated construction; three: grooves: 36' are provided and the same are designated Ag l? and C to indicate the corresponding graduated scales.-

the pointer 34 may be quickly and accuratelylooated in any-witnesaid pre'd('eterlz'iined positions.

Figure- '7? the setting device is shown in broken lines to indicate the manner in which it is used to locate-the spanherhea'd correctly.

It will-be evident that thecalibrationblock' may be provided with any desired number of alternative torque scales 2.6 and that each such scale corresponds to aparti'cularposition of the spannerhead.

'I husin use a box Wrench l-B or other-part engagingtool of the desired size and type isclamped w ther-staining head i l as shown in Figurez7- and ims-uoha position that the axis of a nut engaged thereby will be disposed at; a. predetermined distance from the retainingheadw Thisposition is determined by means oi the setting rod 31 whichais then removed. It -will be noted that, as-thejlongitudinal axis of the spanner is-inclined at an acute angle to the axis of' the lever H], clearance is provided for the inoperative head at the inner end of the wrench;

The wrench I9 is then applied to the work and pressure is: applied by the operator to the hand grip in such a direction that the torque imparted deflects the resilient lever I0 towards the projecting plunger 28 on the abutment arm 21. As previously stated, the position of application of the force is determined by the formation of the hand grip which is so shaped that it is inconvenient to hold in any but the correct manner.

The distance which initially separates the inclined edge of the wedge member 2| from the coacting end of the depressible plunger 28 is determined by the position of the wedge member on the calibrated block and thus for each alternative position of the Wrench head the torque which will cause the operating lever to be deflected sufficiently.

However, the torque required to effect the release of the trip pin 29 may be varied for any particular position of the slidable wedge 2| by altering the effective length of the lever arm-- that is by adjusting the position of the wrench head relatively to the retaining head Hand it is for this reason that the calibrated block is provided with a set of graduations corresponding to each alternative position of the wrench head.

Thus a tension wrench or tool in accordance with the invention is not limited to any particular type of wrench or the like, while additionally it is suitable for wider ranges of torques and nut sizes than existing types of tension wrenches.

It will be understood that, if desired, the retaining head may additionally be formed with a socket of the usual kind to receive the usual type of box wrench though it is preferred to employ separate socket members capable of being clamped to the retaining head in the same manner as the wrench 19 shown in the drawings.

We claim:

1. Torque applying means comprising a resillent operating lever, a handgrip at one end of said lever, a torque transmitting head secured to the opposite end of said lever, clamping means on i said head operabletm secure a part. engaging member thereto ata plurality of predetermined alternative: po's'ltions;such that the distance between the -operative end ofsaid part engaging member and 's'aid handgrip may be regulatedi-a rigid-"abutment member on said torque transmitting-head; signal' meansjinclud'ing coasting: ele meets carried respectively by said abutment member and said operating lever, one of said elements :being ad'justable whereby said signal means will be actuated when apredetermihed torque is applied, means carrying a plurality -o'falternative torque scales corresponding respec tivelyf tb said predetermined alternative positions of the operative endof the part engaging mem= b'er; and: means coacting with said alternative scales and associated with said adjustable ele ment of 'said's'ignal means. I

--2-. Torque-applying means according to claim 1 in combination with locating means attachable theretotodetermine the variousalternative po sitions of the operative end'of the part -engagi-ng member.

3i Torqueapplying means according to-claim l in combination with a: setting member forlo"- eating the operative end of said partengagingmem'ber relativelytosaid torquetransmitting head, said set'ting'member' comprising astraight rod havin'g one end re'ceivable ma socket in'said torque transmitting rod; a pointer "slidable o'n said-rodand means" at spaced positions on said rod; for locating said pointer thereon at prede ter xhin'ed alternative positionscorresponding to said-alternative t'orquescale's. I

4. Torque applying; means according to claim 1 wherein said adjustable element of the signal means comprises a member having an inclined face arranged to coact with said other element of said signal means and wherein one end of the said adjustable element registers with said alternative torque scales.

5. Torque applying means com-prising a resilient operating lever, a handgrip at one end of said lever, a torque transmitting head secured to the opposite end of said lever, clamping means on; said head operable to secure a part engaging member thereto at a plurality of predetermined alternative positions such that the distance between the operative end of said part engaging member and said handgrip may be regulated, a rigid abutment member on said torque transmitting head, visual signal means movably mounted on said rigid abutment member, means on said operating lever bearing a plurality of alternative torque scales corresponding respectively to said predetermined alternative positions of the operative end of said part engaging member and a member adjustably mounted on said means bearing the alternative torque scales and arranged to coact with said signal means and with said alternative torque scales.

6. Torque applying mean according to claim 5 wherein said clamping means on the torque transmitting head comprises a fixed guide and abutment flange disposed at an acute angle to the axis of the operating lever and. a coacting jaw movable towards and from said guide flange.

7. Torque applying means according to claim 5 wherein said member adjustably mounted on said means bearing the alternative torque scales, is adjustable longitudinally with respect to the axis of the operating lever.

8. Torque applying means according to claim 5 including an adjustable pointer secured to said member adjustably mounted on said means bearing the alternative torque scales, said pointer being arranged to coact with said torque scales.

9. Torque applying means comprising a resilient operating lever, a 'handgrip at one end of said lever, a torque transmitting head secured to the opposite end of said lever, clamping means on said head operable to secure a part engaging member thereto at a plurality of predetermined alternative positions such that the distance between the operative end of said part engaging member and said handgrip may be regulated, a rigid abutment member on said torque transmitting head, a calibration block on said operating lever, a, plurality of alternative longitudinally extending torque scales on one face of said calibration block, a member of angle shape in cross section adjustable longitudinally on said calibration block, an inclined face on said adjustable angle shaped member and signal means movably mounted on said rigid abutment member and arranged to coact with said inclined face on the longitudinally adjustable member.

10. In a torque-applying device, the combination of a resilient Operating lever; a head mounted on one end of said lever; means on said head for securing an elongated part-engaging member to said head at a plurality of selected alternative positions along the longitudinal axis of the part-engaging member whereby the distance between the operative end of said part-engaging member and the opposite end of the said lever may be regulated; an abutment fixed on said head; signal means including co-acting elements on said lever and said abutment, respectively, one of said elements being adjustable whereby saidsignal means will function when a predetermined degree of torque is applied; an indicator plate on the part carrying aid adjustable element and having a plurality of alternative torque scales thereon, said scales corresponding respectively to said predetermined alternative positions of said member; and indicating means movable in unison with said adjustable element and relatively to said scales to indicate on the latter the respective torque values for which said signal means is set. ERNEST GEORGE HALLETT. ANDREW CANFIELD BROWN.

REFERENCES crrEn The following references are of record in the file of this patent:

v UNITED STATES PATENTS Number

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