US2289238A

US2289238A - Torque indicating wrench

Info

Publication number: US2289238A
Application number: US293222A
Authority: US
Inventors: Brunelle August
Original assignee: Wright Aeronautical Corp
Current assignee: Wright Aeronautical Corp
Priority date: 1939-09-02
Filing date: 1939-09-02
Publication date: 1942-07-07
Anticipated expiration: 1959-07-07

Description

y 7, 1942- A. BRUNELLE TORQUE INDICATING WRENCH Filed Sept. 2, 1939 INVENTOR flwwrBRz/Mzm 5' ATTORNEY Patented July 7, 1942 UNlTEDf STATES PATENT OFFICE bRQUE lNli l' l iiliG WRENCH V August-:Brunelle, Ridgewood, N. J., assignor to :WrightAei-onautical Corporation, acorporation r of I New York Application September 2, 1939, Serial No. 293,222

-Claims.

This'inventionrelatesito wrenches of the type which are capable ofregistering'the torque applied-thereby and a particular object is to provide means by which the application of a preset torque is indicated to the operator through his tactile sense, rat-her than-requiring his visual observation of meters or dials according to conventional practice. By the use of a tactile indicator, no limitation is imposed on proper torque measurement due'to lighting conditions or accessibility of the parts being worked upon, and indication willdefinitelybeconveyed to the operator without undue concentration by him-onjust one phase of the wrench operation, thus allowing for more expeditious work with increased accuracy. A furtherobject is to provide'means in a torque indicating wrench :byv which; the nut or other part being worked uponwill be firmly seated'atthe desired torque by application of vibrating forces thereto, such vibration being applied only at the desired torque whereby fatigue of. the operator is minimized. Still another object is to provide a torque metering wrench of. rugged and simple designwhich will be adaptable to use over a large range of boltandnut sizes. i In general, torque. metering 1 or indicatin wrenches are usefulin the automotive and aircraft arts, and in others, where mechanisms are highly developed and where it is desired to develop the strength-of screw connections to the fullest extent. It is well known that loose screw connections are subject to failure and further loosening in machine assemblies, while too tight screw connections cause overstressing and failure of materials. Each screw size has an optimum tightness which is difiicult of attainment-without an adequate torque metering wrench This invention provides a wrench which is as easy to use as an ordinary wrench, and which is reasonable in cost.

Additional objects of the invention will become apparent in reading the subjoined detailed description in connection with the drawing, in which Fig. 1 is a plan of the wrench;

Fig. 2 is a longitudinal section on the line 22 of Fig. 1; r

Fig. 3 is a section on the line 3-3 of Fig. 2;

Fig. 4 is a longitudinal section through part of the wrench on a plane normal to that on which Fig. 2 is taken, and

Fig. 5 is an enlarged section on the line 55 I of Fig. 4.

The wrench comprises an end terminal [0 provided with a squared portion H over which the components of socket wrench sets may be assembled, the'terminal'having a transverse hole in which a torque bar I 2 is inserted, the latter being retained in the terminal by suitable means such as a set screw I 3; The bar is preferably of spring steel, and may be any shape or of uniformsection throughout its length. Onthe free end of the bar, a handle I4 is secured, the handle coinprising a hollow, as at I5, and a knurled grip IS, the handle-being slipped over the bar and pinned as at H. A strip or plate l8, having substantial stiffness in the plane of action of the wrench, issecured to the terminal It by a screw IB'a'nd pins 20, the latter securing the strip and terminal against relative rotation. At the free end of the strip I8, 2. laterally extended portion 2| is provided, the substantially arcuate edge 22 of which is calibrated to show applied torque. A guide 24, clamped to the bar l2, carries an adjustable grooved screw element 25 engaged over the edge of the portion 2| to prevent vertical displacement of the strip, and to adjust the contact points later described, this element also serving as an index against which the scale marks on the strip may be observed.

The portion 2!, is formed with a substantially arcuate slot 2'! through which a pin 28 passes, the pin having fiat sides to prevent turning in the slot, having a contactpoint at its lower end 'of a diameter appropriate to embrace the torque tolerance permitted in operating on bolts or nuts, and having screw threads at its upper end. A nut 29 over an index tab 29 serves to secure the pin at any selected position along the slot 21. A second contact point 30 is clamped around the bar 12, insulated therefrom by a strip 3|, the

contacts

30 and 28 being engageable on torque application and bending of the bar 12 to close an electric circuit formed through the strip and bar and through a wire 32 leading into the handle hollow [5 through appropriate drillings therein and in the element 24.

Within the handle is secured a ferrous core 34 by screws 35, a spring armature 36 being secured between the core and handle and extending around the handle bore in clearance relation to carry apole piece 31 and a tapping button 38. Solenoid windings 39 around the core 34 connect to the wire 32 and to one prong 40 secured in an insulating plate 4l' adjacent the handle end, another prong 42 therein being connected to the bar l2 by a wire 43.

Preferably the solenoid is energized by low voltage alternating current through a transformer operating from a conventional lighting circuit, low voltage being used to avoid possibility of shocks to the operator. Alternately, the solenoid may be arranged as a buzzer operating on low voltage direct current, the tapping button comprising a make-and-break contact.

If the device be adapted for higher voltage, the wiring would preferably be insulated, in which case the bar lZ-would comprise 'a tube throughwhich wireflapasses to the terminal I and thence along the strip 18 to the contact 28 which would be insulated from the wrench proper.

The tapping button is preferably, active in the 1 plane of action of the wrench. In operation the operator pulls upon the handle-all :and'ishortlycontacts 28 and 30 engage.to energize-the:sole i' noid 34-49, vibrating the handle to apprise the operator that the desired torque'hasbeenapplied.

The vibration imposed upon the wrench during "slottoward the handle end, an adjustable consaid contacts, and a vibrating armature actuated by said solenoid when energized, said armature having an element for tapping contact with the handle to apprise the operator that predetermined torque has been applied.

3. A torque metering wrench comprising an elastic bar of uniform cross section, a terminal element embracing one end of the ba.r and secured thereto, a handle embracing and secured to the other end of the bar, a relatively rigid strip initially parallel to the bar and secured to said terminalelement, said strip having an arcuate tact element.movable along said slot, a fixed f contactelement secured to the bar and engageable with'the'adjustable contact upon bar bending,asolenoidin said handle in circuit with said application of torque within the deflection range embraced by the

contacts

28, 30 also serves to vibratethe nut or bolt worked upon into a firm seat with its coactingmachine parts.

While I havedescribed myinvention in detail inits' present'preferred embodiment, it will be obvious tothose skilled, in the art, after understanding my invention, that various changes and modifications. may be made therein without departing from the spiritfor scope thereof. Iaim in the appended claimsi to. cover 'alli'such modiiications and changes. U I

Ic'laim;"

'1, A torque metering wrench comprising an elastic bar of uniform cross section,; a terminal= element embracing one end of the bar and secured thereto, a handle. embracing and, secured to the other end of ,the bar a relatively rigidstrip initially para'u m the b r, and secured -to said terminal element, said strip having an arc u-- ate slot toward the handle end, an adjustable contact element movable along said slot, a fixed contact element secured to the bar and engageable with the adjustable contactupon bar bending, an electric, vibratorin said handle in circuit with said'contacts, and an electric power supply:

pluginthe handle end., i

2. A torque metering, wrench comprising anelastic bar ofuniform cross section, a terminal contacts, and a vibrating armature actuated by said solenoid when energized, said armature having an element for tapping contact with the handle] to apprise the operator that predetermined 'torque has been applied, said tapping armature being .so oriented in the handle as to apply'a vibrating force in the, planeof action or the wrench to assist in seating nuts or other devicesto which torque is applied.

4.,iAftorquemetering wrench including-an operating handle and-elements relatively movable in proportion to the torque applied, a vibrator in cured to the guideway, another contactor on the element embracing one end of the bar and -secured thereto a handle embracing and secured to the other end of the-bar, arelatively. rigid strip initially parallel to the bar and secured to 1 said terminalelement, said-strip having an arcuate slot toward the handle end,- an adjustable contact element. movable along said slot but securable at a desired position to the strip, a fixed contact element secured to -the bar and engageable with the adjustable contact ,upon bar bending, a solenoid in saidnhandle in circuit with other member, said-contactors being engageable over aselected narrow range of deflection as one member is deflected relative to the other upon torque application to the elastic member, said contactors being disengaged from one another upon torqueapplication less than or greater than that necessary to cause the contactors to meet in said narrow range oideflection, electric signalling means actuated by engagement of said contacts,janda hollow handle on the end of the elastic member within which said signalling means is-disposed.

a AUGUST BRUNELLE.