US2662436A - Predetermined torque release socket wrench - Google Patents

Description

Dec. 15, 1953 o. B. HARMES PREDETERMINED TORQUE RELEASE SOCKET WRENCH Filed April 28, 1952 Bill E Patented Dec. 15, 1953 UNIT E D1.- STATES PATENT E F 1 CE PREDE-TERMINED' TORQUE RELEASE SOCKET. WRENCH Oren B. Harmes; Algona, Iowa, assignor to LivingstonToolt 00., Algona, Iowa, a. partnership Application April.2,8,. 1952, SerialINO. 284,781

8 Claims;

This invention relates to: torque wrenches. More particularly, it relatesto wrenches for-automatically releasing themselves when a prede termined high torque is exerted thereupon.

This invention is an improvement'on my invention entitled Torque Wrench filed by me April- The torquewhereupon only a small" or moderate amount of torque is to be exerted. My present invention as disclosed and claimed herein constitutes an improvement upon my invention disclosed in my previous application with respect to torque wrenches in general and more especially"- with respect totorque wrenches constructed and to be used for imposing ahigh torque upon the elements to be turned thereby;

Various wrenches have been constructed previously for the purpose of applying a'torque to an element to be turnedand some of these are automatically releasable: None of these, however; to the applicants' knowledge; are adapted for applying a high torque to the element to be turned and to automatically release itself when a predetermined high torque is applied to thatelement. All of the automatically releasing torque wrenches knownto the applicant prior to the instantinvention are adapted solely for usewith small-L tomoderate amounts of torque.

It is" a general object of my invention to provide a novel and improved torque wrench of cheap and simple construction.

A. more specific object is to provide'anovel and improved torque wrench which will require ahigh torque before it automatically releases.

Another object is to provide a torque wrench requiring high torquefor'its release and in which adjustment may be made to cause thewrench to release at any desired predetermined high torque:

Another object is to: provide anovel and improved: high torque wrench of compact size and capable of ready adjustment to release at other predetermined high torques. 7

Another object is to: provide a high torque wrench. which may be quickly: and; easily reset after its release.

These and other: objects and advantages of my invention. wiil. more fully appear from thefoilowing description. made in connectionwith the accompanying drawings; wherein like reference characters refer. tosimilar parts through out. the several views;. and. in which:

Fig. l is a longitudinal sectional View of one embodiment of my invention with a portion of the handle broken away;

Fig. 2 is a fragmentary side elevational view of the same with the head member shown in longitudinal section taken in a plane at right angles to the plane shown in Fig. l; and

Fig. Bis a top plan view of the head member with the top plate intact and of the interior shank portion of the handle.

One embodiment of my invention may include, as shown in Figs. l-3, an interiorly tapped handle member indicated generally as H and having rigidly secured thereto at its outer end a head member 6. The head member 6- lras a hollowed out portion 1 formed therein, this hollowed area beingsomewhat elongated but generally circular at each of its end portions as best shown in Fig. 1 and indicated by thenumeral 3. An opening Ba is formed in the bottom wall of the hollowed out head member so that a passage extends transversely through the head member 6. This is best shown in Fig; 2. A second opening 8b is formed in the-bottom wall to receive a pivot pin to be-hereinafter described. Mounted for rotation in the outer end portion of the head memher is a rotatable body or socket 9. This socket 9 has an opening It extending therethrough of the proper size" and shape to engage the element' desired to be turned by the wrench. The socket 9 has a central circumferential rib H which provides a shoulder 52 to cooperate with the portions Iii of the bottom wall which define the opening 8a tohold the socket from sliding outwardly from the head member 6.

A plate M is secured to the other side of the head member by cap screws i5, this plate having anopening I6 therein. of suificient size to permit the outer edge portions of the socket to extend outwardly therethrough. A smaller opening M's. is also: formed in the plate it to receive the pivot pin previously referred to and to be hereinafter described; Formed in the outer circumferential surface of the central rib ii of the socket ii are a plurality of" ratchet teeth it which are directed in a general direction around the socket member (this direction being shown as clock-wise in Fig. 1). Absent any engaging element-cooperating with these ratchet teeth ['5 the socket ii -is free to rotate: in the hollow portion a of the'head' member but is confined to that portion.

The handle H is comprised of a shank it which, as shown in Fig. 1, is formed integrally with the head member 6. This shank l8 has a longitudinally extending-bore 19 which communicates with the hollowed out portion 7 of the 3 head 6 and which extends throughout the entire length of the shank. The medial portion of the shank I8 is externally threaded as at 20 while the rearward or inward portion is reduced as at 2|. The extreme inner end of the shank I8 is provided with a pair of inwardly extending shoulders 22 which are disposed opposite each other as best shown in Fig. 1 and Fig 3. The shank I8 is graduated as at 23 along the circumferential surface of its outer end portion.

The other section of the handle H is internally threaded as at 24 to cooperate with the external threads 20 of the shank Is as best shown in Fig. 1. This section has an interior bore extending inwardly from its outer end and of suflicient diameter to accommodate the shank 18. The bore is of suiiicient length to also accommodate a relatively strong spring 25 which is maintained at its inner end in central position with respect to the bore by a plug 26 having a reduced head 21 adapted to be inserted within the spring. Also formed in this section of the handle is a readin hole 28 which, when the two sections of the handle are threaded together, moves directly opposite the graduations at 23 on the shank Hi. This section also has an internally threaded aperture 29 adapted to receive a set screw 30 opposite the reduced portion 2| of the shank l3. Mounted for limited sliding movement within the shank H! of the handle H is a rod 3| as best shown in Fig. 1. The inner end of this rod is externally threaded as at 32 to threadedly receive a nut 33 of external diameter equal to the spacing between the opposed shoulders 22. As best shown in Fig. 1, this rod 3| is of sufficient length so that its inner end extends inwardly beyond the shank I8 and a nut 33 is received at the outer end of the spring 25 and is of sufficient length so that its outer end 34 extends into the hollowed out area of the head member 6.

The outer end of the rod 3| is flattened and reduced as at 35 to receive the inwardly extending bracket arms 36 of a toggle member indicated generally as T. The bracket arms 36 are spaced from each other to accommodate the flattened portion 35 therebetween and have apertures formed therein to accommodate a pivot pin 31 which extends through each of the arms 36 and the flattened portion 35. This pivot pin 31 is arranged to extend transversely with respect to the rod 3| and on an axis substantially parallel to the axis of rotation of socket member 9.

The toggle member T is provided with an outwardly extending circumferential shoulder 38 and is further provided at its outer end portions with a cylindrically shaped key 39. This key 39 extends transversely with respect to the rod 3| and substantially parallel to the pivot pin 31. A relatively weak spring 43 is carried by the outer end 34 of the rod 3| and by the inner end of the toggle member T. This spring abuts against the shoulder 38 and against the wall of the head member which defines the hollowed area 1. The walls of the hollowed area i are suliiciently spaced from the toggle member T so that the latter may swing sufficiently far to either side of the longitudinal center of the rod 3| to cause the key 33 to become completely disengaged from the lever member to be hereinafter described.

Pivotally mounted between the bottom wall of the head member 3 and the plate I 4 upon a pivot pin 4| is a lever member indicated generally as 42, this lever member being in the form of a dog. The pivot pin 4| is pivotally mounted for free pivotal movement in the openings 8b and |4a of the bottom wall and top plate l4 respectively. A reset arm 43 extends transversely to the pivot pin 4| and outside the bottom wall of the head member. This lever member or dog 42 has a tooth 44 of suflicient length so as to engage the teeth I! of the rotatable body or socket 9. Its opposite end portion has a recess 45 formed therein and is adapted to engagingly receive therein the key 39. This recess 45 is so positioned that when the recess is to one side of the longitudinal center of the handle H the toggle T is also swung to that side. This can best be seen in Fig. 1. It should be noted that the lever member 42 actually constitutes a lever with the fulcrum 46 being at the center of the pivot pin 4|, the shorter lever arm being that portion 01 the lever or dog which carries the tooth 44 and the longer lever arm being that portion of the dog which carries the recess 45.

When the wrench is assembled for use the respective parts are in the relation to each other as best shown in Fig. 1. By referring to Fig. 1 it can be seen that the section of the handle which receives the shank portion I8 is threaded onto the shank sufliciently far to exert the desired compression on the spring 25. When this has been done the set screw 3|] is tightened and thereafter the socket 9 will be prevented from turning by the toggle T and the lever arm 42 until a sufficiently high torque has been exerted thereon to cause the toggle T to cam over and the lever arm 42 to pivot about its fulcrum 46 to the dotted line position shown in Fig. 1, thereby compressing the spring 25. It can be readily seen that in normal position the toggle T extends diagonally with respect to the rod 3| and is constantly urged toward engaging relation with respect to the lever arm 42. It can also be readily seen that the lever arm 42 extends diagonally with respect to the rod 3| but in the opposite direction to the direction in which the toggle member T extends and is constantly preventing the socket member 9 from rotating in the direction in which its teeth I! extends. At the same time the spring 25 constantly urges outwardly against the nut 33 to tend to prevent the rod 3| from being moved inwardly and to simultaneously, of course, tend to prevent the toggle mechanism T and the lever member 42 from swinging over to disengaging position shown in broken lines in Fig. 1.

In operation, the wrench is arranged so that the socket 9 will engage the bolt, nut, pin or other element desired to be rotated. The necessary torque is then applied to the handle H to rotate the elements. So long as the resistance offered by the element being turned does not exceed a predetermined torque arrived at by the amount of compression placed upon the spring 25 and the purchase obtained through the use of the lever arm 42 and the toggle mechanism T, the wrench will continue to tighten the element. This amount of torque will necessarily be relatively high because the amount of purchase attained through the use of the lever member 42 is so great as to require an unusually high amount of torque to cause the toggle T to swing over to disengaging position. However, when this predetermined torque is exceeded the toggle T will cam over to the opposite side and in so doing will compel the rod 3| to move inwardly, overcoming the outward thrust of the spring 25. By camming over, the toggle T automatically, for all practical purposes, causes the lever member 42 to release the socket 9 since a much lower torque will be required to cause the socket to rotate relative to the tooth 44 when the tooth is swung to the position shown in broken lines in Fig. 1. Thus it can be seen that the socket member 9 is free to rotate relative to the handle H after the toggle T has swung to the broken line position.

After the toggle T has cammed over, the wrench can be immediately reset for use on the next element by swinging the reset arm t3 back to its original position, thereby causing the longer lever arm of the lever member 42 to thrust the toggle mechanism T back beyond its original position until the key 39 can again slip into the recess 15. When this is done the tooth member 4 3 will again beengaging the ratchet teeth ii of the socket member 9 and the wrench is again ready for use.

The torque required to cause the toggle T to cam over may be predetermined at various degrees of compression exerted on the spring 25 and the same may be indicated on the shank it by graduating the shank as indicated in Fig. 3. Thus the user may readily adjust the compression exerted on the spring 25 by tightening or loosening the portion of the handle carrying the set screw with respect to the shank in. When the handle has been adjusted so that the desired torque will be required to cause the toggle T to cam over, that fact will be indicated by reference to the reading opening 28 as shown in Fig. 2. Thus it is possible to adjust the wrench readily to cam over at various predetermined torques.

Thus it can be seen that it becomes impossible with this Wrench regardless of carelessness or adjustment in the use of wrenches to tighten a given element beyond a predetermined high torque for the socket 9 will automatically be released as soon as that predetermined torque is exceeded. At the same time it is possible to tighten elements which require a high torque and yet to have the automatic release feature available. In other words, it is now possible, through the use of my wrench, to tighten a given element to a high degree of torque with full assurance that when that torque is reached there is no danger of exceeding the same.

It should be noted that my wrench is also adjustable to compensate for changes which may take place over a period of time in the resistance which the spring 25 offers to compression. By adjusting the nut 33 on the thread end of the rod 3| the amount of compression can be changed even though the two sections of the handle remain in the same position with respect to each other.

It should be noted that I have provided a torque wrench which is cheap and simple to construct and which may be quickly and easily reset after its release. My torque wrench is constructed to exert a high torque previously impossible in torque wrenches and to automatically release this torque when a predetermined limit is reached. This positively prevents the element being tightened by the wrench from being damaged seriously. It is highly important in various assembling operations wherein the particular material being used is of such a nature as to rupture when a predetermined torque is exceeded. My wrench provides a ready and eiiicient means for accomplishing this function. For example, it is imperative today in the installation of spark plugs that the plugs be inserted with a high torque in order to insure long life of the plugs. When the plugs are installed merely through guessing at the amount of torque applied thereto there is constant danger that either insufficient torque will be used or that the plug itself will be damaged by an excess of torque being applied thereto. My wrench positively prevents the occurrence of such damage or improper installation and enables even the most unskilled type of laborer to install spark plugs at the optimum torque.

It should also be noted that my wrench, despite the fact that it is possible of exerting unusually high torque upon a given element and is capable of automatically releasing when a predetermined high torque is attained, is very compact and rela tively simple to manufacture. In spite of its simplicity, compactness and inexpensiveness, it is a highly efficient tool which takes the risk out of tightening elements to a high torque because the element of guess-work is completely removed.

It will, of course, be understood that various changes may be made in the form, details, arrangement and proportions of the various parts without departing from the scope of my invention.

What is claimed is:

1. An automatically releasing torque wrench comprising a handle member, a rotatable body mounted for free rotation upon said handle member adjacent one end thereofand adapted to be connected to the element to be turned by the wrench, a movable lever member carried by said handle member adjacent said rotatable body, a portion of said lever member engaging said ro tatable body to ordinarily prevent its rotation,

and resilient mechanism normally urging said portion of said lever member in a predetermined direction about its fulcrum to yieldably hold said rotatable body against rotation in the opposite direction so long as a predetermined torque is not applied thereto, said portion of said lever member being swingable into non-engaging position relative to said rotatable body when such predetermined torque is applied to said rotatable body to permit the latter to thereafter turn without being re-engaged by said portion or" said lever.

2. An automatically releasing torque wrench comprising a handle member having a head portion at one end thereof, a rotatable body mounted for free rotation upon said head portion of said handle member and having outwardly extending teeth on the outer circumferential surface thereof and adapted to be connected to the element to be turned by the wrench, a movable lever member carried by said handle member adjacent said rotatable body, a portion of said lever member engaging said teeth of said rotatable body to ordinarily prevent its rotation, and resilient mechanism normally urging said portion of said lever member in a predetermined direction about its fulcrum to yieldably hold said rotatable body against rotation so long as a predetermined torque is not applied thereto, said portion of said lever member being swingable into non-engaging position relative to said rotatable body when such predetermined torque is applied to said rotatable body whereby said body will thereupon become freely rotatable relative to said handle member without being re-engaged by said portion of said lever.

3. An automatically releasing high torque wrench for applying a high torque to an element 1 to *b-turned, said ;wrench' comprising a handle member having a head portion thereupon; a rotatable body mounted for free rotation upon said head portion of said handle member and. adapted to be connected to the element to be turned by the wrench, a movable first-class lever member carriedby said handle member. adjacent said rotatable body and having a longer lever armand a lever member, a portion ofsaid lever member engaging said: rotatable bodyto ordinarily prevent" its. rotation, and resilient means normally urging said portion of said lever arm in a predetermined direction' about its fulcrum to yieldably-hold said rotatable body against rotation in the opposite direction so long asa predetermined torque is not applied thereto, said resilient means including toggle mechanism extending normally diagonally to saidlever member and engaging the longer leverarm of said lever'member to insure that said rotatable member will not be permitted to rotate until a predetermined high torque is applied thereto, said shorter lever arm being swingable into non-engaging position relative to saidbody when such apredetermined high torque is appliedto said body to. permit the latter to thereafter turn without being re-engaged by said portion of said shorter lever. arm.

4. An automatically releasing torque wrench comprising a handle member having a head por tion at one end thereof, a rotatable body mounted for rotation upon said head portion of said handle member and adapted to be connected to the-element to be turned by the wrench, a movable firstclass lever member carried by said handle memberandpivoted at its fulcrum adjacent said, rotatable body, the shorter end portion of said lever member engaging said rotatable body to ordinarily prevent its rotation, a rod slidably mounted within said handle member, togglemechanism connected to one end of said rod and normally extending diagonally thereto and engaging the longer end portion of said lever member and normally urging the'same in a predetermined direction, and resilient means normally causing said toggle mechanism to urge said longer end portion of said lever member to-move in a predetermined direction about its fulcrum to yieldably hold said rotatable body against rotation in the opposite direction so long as a predetermined high torque is not: applied thereto. 1

5. An automatically releasing high torque wrench for use in applying a high torque to an element to be turned, said wrench comprising a handle having a head member at one end thereof, a rotatable bodymounted for rotation upon said head member of said handle and adapted to be connected to the element to beturned by the wrench, a first-class lever member movable about its fulcrum and carried by said handle adjacent saidrotatable body, said lever member comprising a dog pivotally mounted at its medial portion uporrsaid headmember and-having a-longer lever arm; and a shorter lever, arm, the shorter lever arm of; said dogengaging said Wrench body to ordinarily prevent its rotation, and the longer lever arm of said dog having a recess formed therein, a shank slidably mounted within said handle, toggle mechanism positively connected to one end. portion of saidshank and normally extending diagonally thereto and engaging said longer lever arm of said dog in its recess, and resilient means normally urging said longer lever arm of said dog in a predetermined direction about-its fulcrum to yieldably hold said rotatable body against rotation in the opposite direction so 1mg as a predetermined: torque is not applied thereto. a

6. An automatically releasing high torque wrench for use in applying a-high torque to an element to .beturned, said wrench comprising: a handle member having an atleast partially hollow head member at one end thereof, a rotatable body. mounted for free-rotation upon said head member of said handle and adapted to be connected to the element to be turned by the wrench and having ratchet teeth. formed on its circumferential portions, a shank slidably mounted within said handle and extending toga point adjacent to the hollow portion of said head member, toggle mechanism connected to said shank and normally extending diagonallywith respect thereto and lying within said hollow portion of said head member, and a first-class lever member pivotally mounted by its medial portion upon said head member and having a longer lever arm and a shorter lever arm, said longer lever arm being engaged by said toggle mechanism, said shorter lever arm engaging the ratchet teeth on the circumferential portions of said rotatable body, and resilient means normally-urging said rod toward said rotatable body and causing said toggle, mechanism to urge said longer lever arm of said lever member ina predetermined direction about its fulcrum to cause said. shorter lever arm to yieldably hold said rotatable body against rotation in the opposite direction so long as a predetermined torque is not applied thereto, said shorter lever arm being swingableto non-engaging position when such predetermined torque is applied to said body to permit the latter-to thereafter rotate freely in the direction of the torque without being re-engaged by said shorter lever arm.

7. An automatically releasing high torque wrench comprising an at leastpartially hollow head member, a rotatable body mounted for free rotation in the ,hollowportion-of said head mem-' her and adapted toengage the element to be turned by the wrench, ahandle member rigidly secured to said head member and having a central longitudinally extending bore adjacent to and communicating with said-hollow'portion of said head: member, a shank member mounted within said bore for limited sliding movement therewithin and being constantly and yieldably urged toward said rotatable body, toggle mechanism swingably connected to the outer end of said shank member,- and a movable lever member interposed between said toggle member and said rotatable body, a portion of said lever member being engaged by said toggle mechanism and being normally urged, therebyto move in a predetermined direction about its fulcrum and another portion of said lever member engaging said rotatable body to ordinarily prevent its rotation in the opposite direction, said lever member when the wrench is in use moving its last mentioned portion to non-engaging positionrelative to said rotatable body when a predetermined torque-is exceeded'to permit said rotatable body to rotate freely in the direction of the torque without being re-engaged by said last mentioned portion.

8. An automatically releasing torque wrench comprising an at least partially hollow head member, a rotatable body mounted for free rotation in the hollow portion of said head member and adapted to engage the element to be turned by the wrench, a handle member rigidly secured to said head member and having a central longitudinally extending bore adjacent to and communicating with said hollow portion of said head member, a rod mounted within said bore for limited sliding movement longitudinally of the handle, a toggle member swingably connected to the outer end of said rod and normally extending at an angle thereto and having an engaging element on the outer end portion of the same, resilient means constantly urging said rod toward said rotatable body, a movable lever member interposed between said toggle member and said rotatable body, a portion of said lever member being engaged by the engaging element of said toggle member to urge said lever arm to move in one direction and the other portion of said lever member engaging said rotatable body to ordinarily prevent its rotation in the opposite direction, said lever member functioning to move said last mentioned portion to non-engaging position relative to said rotatable body when a predetermined torque is exceeded to permit said rotatable body to rotate freely, and manual resetting mechanism connected to said lever member and extending outwardly of said head member whereby said lever member may be readily returned to engaging position with respect to said body.

OREN B. HARMES.

References Cited in the file of this patent UNITED STATES PATENTS

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