US2958246A

US2958246A - Ply wrench

Info

Publication number: US2958246A
Application number: US784188A
Authority: US
Inventors: Leonard C Osborn
Original assignee: Gardner Machines Inc
Current assignee: Gardner Machines Inc
Priority date: 1958-12-31
Filing date: 1958-12-31
Publication date: 1960-11-01
Anticipated expiration: 1977-11-01

Description

L. C. OSBORN Nov. 1, 1960 PLY WRENCH 2 Sheets-Sheet 1 Filed Dec. 31. 1958 Nov. 1, 1960 c, s o 2,958,246

PLY WRENCH Filed Dec. 51, 1958 2 Sheets-Sheet 2 FIG. 2

INVENTOR Leonard 6. Osborn PLY WRENCH Leonard C. Osborn, Salt Lake City, Utah, assignor to Gardner Machines, Incorporated, Salt Lake City, Utah, a corporation of Utah Filed Dec. 31, 1958, Ser. No. 784,188

8 Claims. (CI. 81-99) The present invention relates to wrenches and more particularly to improvements in wrenches of the type having a fixed head and a movable jaw for gripping an object so that the object may be rotated by force applied at the handle of the wrench.

An object of the present invention is the provision of a ply wrench which is easily manipulated and engaged with the workpiece that is to be grasped.

Another object is the provision of a wrench of the character indicated in which the movable jaw is susceptible to being opened backward on its pivot by contact with the workpiece or object so as to afford the needed gap with the fixed head for the wrench to accommodate and engage the object in its grasp.

Another object of this invention is the provision of a ply wrench in which practical and effective jaw biasing means is included and is well concealed inside the wrench in the interests of compactness, being effectively installed and protected.

A further object is to provide a ply wrench having movable jaw biasing means that in being assembled with the other components of the wrench may be readily wound and anchored for operation.

Another object of this invention is the provision of a ply wrench in which the movable jaw is rotatable through a remarkably long range of positions where gaps of different dimensions are formed with respect to the fixed head, and the gripping surface of the movable jaw for each of the positions in this range is generally parallel to a tangent drawn to a corresponding opposite point on the gripping face of the fixed head.

Another object of this invention is that of providing a ply wrench which is thoroughly capable of accomplishing a positive well directed gripping action on such ob jects as pipes, rods, or the like, conducive to freedom from slipping.

A further object of the invention is that of providing a ply wrench of the character indicated having positive gripping characteristics and is enhanced by having good force transmission from the handle to the surface of the object being grasped.

Another object is that of providing a ply wrench of the character indicated that is easy to make and assemble.

Other objects of the invention in part will be obvious and in part pointed out more fully hereafter.

The invention accordingly consists in the several components, combination of elements, and features of products, and in the relation of each of the same to one or more of the others, the scope of the application of which is indicated in the following claims.

In the accompanying drawing representing a particular embodiment of the present invention:

Figure 1 is a side elevation of a ply wrench with a portion of the handle omitted and with the movable jaw in an open position with respect to the fixed head;

Figure 2 is a front elevation of the wrench in Figure 1 with the lower portion of the handle omitted; Y

Figure 3 is a side elevation correspondingto Figure. 1,

2,958,246 Patented Nov. 1, 1969 with a portion of the handle omitted and with the movable jaw of the wrench in a forward stopped closed position with respect to the fixed head;

Figure 4 is a transverse sectional view of the wrench taken along 44 in Figure 3; and v Figure 5 is a diagram representing certain preferred relations geometrical-1y for different positions of the movable jaw, which exist between the fixed head, movable jaw and handle of the wrench.

As conducive to a clearer understanding of certain features or the present invention, it may be noted at this point that ply wrenches of the type having a handle, a fixed head and a movable jaw have heretofore been used in one form or another for gripping and rotating objects such as pipes or rods. These wrenches are intended to develop a gripping force against the object that is to be engaged and rotated with the aid of the handle of the wrench, and the gripping force is developed from force applied at the handle.

The present invention introduces improvements over the prior art and these improvements will be more readily understood in view of the illustrative embodiment represented in the accompanying drawing, in which a form of ply wrench is designated generally by reference numeral 10. The wrench is produced from steel such as a stainless variety or of other suitable material or materials, and includes a handle 11 having an integral fixed head 12 at one of its ends. In profile (see Figures 1 and 3), head 12 is widened outward from the handle and includes front and

back edges

14 and 15 which extend outward from transitions respectively with front and

back edges

16 and 17 of the handle and then merge with an outwardly curved edge portion, the latter including a substantially arcuate gripping face 13. The

inclined edge portions

14 and 15 preferably are also curved, and in inward directions back to the handle. A movable jaw 18 of the wrench comprises spaced

opposed legs

19 and 20 pivotally attached to the handle 11 at the fixed head portion 12 by a pivotal connection 21. The pivotal connection is disposed toward the back of the handle and fixed head from the radial center of the curved gripping face 13. Legs 19 and 20 overlap opposite sides of the fixed head 12 and merge integrally at a nexus 22 with an outer portion 23 of the movable jaw. Jaw portion 23 has a forward outer tip 24 and a straight gripping face 25 extending back from the vicinity of the tip end 24. The straight gripping face 25 is aligned with the curved gripping face 13 of the fixed head and is in substantially L-disposition with respect to the

legs

19 and 20 of the movable jaw.

The movable jaw preferably is biased with a reasonable amount of force for closing forward automatically against the fixed head 12 and for this purpose the pivotal connection 21 advantageously includes a pivot pin 26 having a head 27 on one end and a cylindrical shank 28 extending from the head. Shank 28 has a slot 29 extending backward from its free end for reasons which will be explained more fully hereafter. There are axially aligned

apertures

30 and 31 respectively through the end portions of

legs

19 and 20 of the movable jaw 18 and these apertures are only slightly larger than shank 28 so as to accommodate the shank with the head 27 abutting the base of outside leg 20 and the slotted end of the shank terminating substantially flush with the outside face of leg 19. A transverse bore 32 entering the side face of fixed head 12 accommodates the corresponding portion of shank 28 but is slightly larger so that the adjacent bore surface of head 12 will serve as a fixed bearing for the pin. A relatively large coaxial counterbore or chamber 33 merges with bore 32 and provides a step 34 inside the fixed head 12. Bore 33 extends to the side face of head 12 which is opposite the face of the head.

3 that bore 32 enters. A convoluted spring 35 made for example of spring steel wire and having helical turns is situated inside the bore 33 and is provided with a longitudinal end 35a engaged in an aperture 38 drilled into fixed head 12 through the face of step 34. An opposite transverse end 35b of the spring is engaged in slot 29 of the pivot pin 26. A bearing ring 36 for pin 21 is introduced over the shank of the pin and fits against the surface of the fixed head 12 which forms the wall of the enlarged bore 33. The bearing ring also closes off the outer end of bore 33 with the spring occupying a position between the bearing ring and the step 34. A small key 37 is provided to fit into the end of slot and the key is employed .to rotate the shank preferably while the movable jaw is in its fully closed position with respect to the fixed head of the Wrench, the rotation being in favor of winding the helical spring to developa biasing force that will hold the movable jaw forcefully closed and somewhat resist backward rotation of the movable jaw with respect to the fixed head. Then with the spring properly wound, key 37 is driven inward into the slot and an elongated outer end portion 37a of the key enters and engages a notch 19b in leg 19 of the movable jaw. 'I'hus, assembly is maintained with the spring held wound by the key. The pivot pin 26 cannot escape until the key 27 is dislodged. Dislodgment can be accomplished as with the aid of a punch applied to the exposed end of the pivot pin shank 28 and by striking the punch with a hammer.

In the closed position of the movable jaw 18 (see Figure 3) the forward end 24 of the jaw is in the vicinity of a prolongation of straight line CD which extends through the axis of pivotal connection 21 and through radial center 40 of the substantially circular gripping face 13. The forward tip 24 in this position is spaced outward from the inclined forward edge portion 14 of the fixed head to serve as a claw on the movable jaw with the forward inclined edge 14 of the fixed head converging with the straight gripping face in approaching that face. The distance of offset of tip end 24 advantageously is that needed to produce a gap with edge portion 14 at least equal in width to about half the maximum effective gap the movable jaw forms with the curved gripping face 13 when the jaw is rotated backward. Thus, with the movable jaw 18 closed, the forward edge portion 14 of the fixed head may be placed against a pipe or the like which is to be grasped and the tip 24 of the movable jaw is brought into simultaneous contact with the object and can be forced back by manipulating the handle 11. The pipe or other object will ride on edge 14 of the fixed head as the movable jaw 18 opens and then ridesbackward on the curved gripping face 13 as the opening continues. Thus, the pipe or the like finally is in a needed gap for being gripped between the straight gripping face 25 and the curved gripping face 13. A forward push or pull on the handle if then causes the object to be gripped and an additional force in the same direction causes the object to be rotated while gripped.

Straight gripping face 25, the curvature of gripping face 13, and pivotal connection Iii advantageously are so geometrically related that a normal drawn to the straight gripping face to a point where gripping of an object is to occur between the front and back ends of that face, intersects the effective length of the curved gripping face at a succession of points for a substantial range of rotation of the movable jaw on its pivot and, further, the normal in extending through each of the successive points on the curved gripping face, passes adjacent to or substantially through the radial center of the curved gripping face. It follows that in this range a tangent drawn to each of the succession of points of intersection of the normal with the curved gripping face is generally parallel to the straight gripping face for the movable jaw and fixed head to applyforce to the object in substantially direct opposition.

r a diameter CD extending through the radial center.

A mathematical principle illustrating a satisfactory approximation of the above-identified conditions, and a basis on which wrench 10 often is constructed, now will be explained with reference to Figure 5 of the drawing wherein a circle is shown having a radial center 0 and A pivot point A is disposed on diameter CD between the radial center 0 and the perimeter of the circle just mentioned. Line AR extending from point A is intersected by a normal RF. -A perpendicular PN to line RF is drawn from point P and the perpendicular passes through the radial center 0 of the circle when angle x, the angular displacement'about point A of line AR forward from line CD, is equal to Thus, the distance d measured laterally between the normals AR and PN is equal to the distance A0 existing between point A and the radial center 0 of the circle. A tangent ST drawn to the circle at point M where line PN intersects the circumference of the circle is parallel to RF when angle x equals 90. When angle x is increased or decreased from the 90 value, however, the normal PN gradually moves away from and thus no longer intersects radial center 0 of the circle and the tangent ST or S"T" drawn through the corresponding point M or M" on the circle is no longer parallel to line RF. This can be demonstrated by letting angle y equal the angle which is formed by the intersection of line RF and the corresponding tangent drawn to the circle for a given value of angle x and by referring to the following equation:

d-d sine a: sme y=-- in which d equals'the lateral distance between normals RA and PN, and r equals the radial length of the circle having center 0.

When angle x in the equation decreases from 90 toward 0 or is increased from 90 toward angle y increases, though for a considerable range of values of angle at extending uniformly both ways from 90, the value of-angle y indicates substantial parallelism between line RF and the corresponding tangent to the circle.

Thus, in providing wrench 10, I prefer to interrelate the straight gripping face 25 and a major portion of the effective length of curved gripping face 13 so that for values of angle x, as described, the corresponding values of angle y are less than approximately 10 maximum for maintaining substantial parallelism of the plane of the straight gripping face and the corresponding tangent to the curved gripping face. The curved gripping face 13 accordingly has a radial center 0 (see Figure 5) removed a lateral distance d from the center A of rotation afforded by pivotal connection 21 for the movable jaw 18. A normal drawn to line CD at center 0 substantially bisects the effective gripping length of the curved gripping face 13. The effective gripping length of the curved face '13 advantageously is approximately at least 25 of are measured about center 0 in each of opposite directions from the normal drawn to the line CD at center 0, thus giving a total length of arc of at least about 50 which is effectively shared by the area of the straight gripping face adjacent to point P for forming a variety of gaps of different widths that accommodate objects of any of a large number of different sizes. Distance d is measured on diameter CD drawn through points 0 and A, which diameter corresponds to a circle including the curved gripping face 13 of the fixed head. Line AR represents a normal drawn from the center of rotation A of the movable jaw to a prolongation of the plane of the straight gripping face 25, intersecting that plane at point R. Line PN drawn normal to the straight gripping face 25 at a point P, in the effective gripping area of the straight gripping face, passes through the radial center '0 of the circular gripping face 13 when angle or --is -equal to-about 90. Thus'line ST-drawn tangent to the circular gripping face where the normal PN from the straight gripping face intersects is approximately parallel to the straight gripping face when angle x is equal to about 90. The value of d, this being the distance between the normals RA and PN, is susceptible to variation from wrench to wrench depending upon such factors as the length of the straight gripping face desired and the position where point P is to be situated along the length of that face for the normal PN to be effective. It will be appreciated too that variations in distance d from wrench to wrench, other things for example being equal, are availed upon to tolerate extending the effective length of the curved gripping face 13, and this is illustrated by the following table identifying the approximate x values, that, for maximum angle y values, correspond to certain d values in the range of d=0,3r to 0.9r. In order to keep point P well offset from the back of the movable jaw, distance d magnitudes of about 0.5r to 0.91- are preferred, r, of course, being the radial length of the curved gripping face 13.

d Angle z Angle 1 About 10 max. About 10 max. 55 to 125 About 10 maxi The radial length of the movable jaw as represented by the length of line RA also is susceptible to variation from wrench to wrench in order to produce different jaw gap dimensions within desired ranges of angle x.

As illustrative of a more specific embodiment, wrench 10 has point P on the straight gripping face of the movable jaw so located as to be about twice the radius r of the curved gripping face 13 outwardly removed from the radial center of the latter face when the normal PN intersects the curved gripping face at point -M (see Figure 5) near the inner effective end of the arcuate gripping face 13. Point P is offset forward about half the maximum or substantially full open gripping gap of the wrench from the back inside edge 25b of the movable jaw, and this same point as will be noted in Figure 5 is about midway along the length of the straight gripping face. Center A of the pivot 21 is about 0.6r from the radial center of the curved gripping face 13. A length of wrench gripping face 13 available to point P on the straight gripping face accordingly ranges between beginning end or back point M and the forward M, the distance between the latter two points being defined by an arc of approximately 70 with respect to the radial center 0, this preferably being about 35 of arc on each of both sides of the approximate midpoint M (see Figure 5) of gripping face 13. As movable jaw 18 is closed to the Figure 1 position from an open position, point P on the straight gripping face moves forward of point M" (see Figure 5), but by extending the general curvature of the gripping face 13 beyond point M and by having this curvature thereafter merge by reversing into an inwardly curved forward edge 14 of the fixed'head, a length of the curved gripping face forward of point M is available to share a gripping action which may be exerted in conjunction with points behind point P on the straight gripping face 25. Relatively small objects accordingly can be gripped in the latter areas of the wrench and the gripping force, as applied, still is exerted approximately through the radial center of the arcuate gripping face. When the movable jaw 18 is in its full closed position with respect to fixed head 12, the nexus 22 of the jaw legs 19 and 2t) abuts the head and accordingly prevents any further forward rotation of the movable jaw. It is interesting to note that by substituting 0.62, the value of a in this instance, in the equation hereinbefore noted for solving for angle y, and by introducing angle x values within the range of about to 125 (indicative of the 70 arcuate gripping face) a corresponding range of angle y values is obtained which do not exceed about 8 maximum. The longitudinal axis of handle 11, when prolonged, preferably passes adjacent to the radial center of curved gripping face 13 and intersects the curved gripping face near the inner effective end of the latter, although other angles of inclination of the handle with respect to the curved gripping face may of course be used in accordance with the practice of this invention.

While considerable emphasis has been placed upon the provision of wrenches which include a circular gripping face, it will be distinctly understood that the invention also includes Wrenches having an approximately circular gripping face produced by modifying a circular curvature to the extent of making the angle y values, referred to, smaller values even down to zero values throughout the intended useful length of the curved gripping face. Under these conditions the value of r would remain as the approximate radial length of the circular curve which is being modified.

As many possible embodiments of this invention may be made and as many possible changes may be made in the embodiment hereinbefore set forth, it will be clearly understood that all matter described herein is to be interpreted as illustrative and not as a limitation.

1 claim:

1. A ply wrench comprising a handle and fixed head unit, a movable jaw provided with legs overlapping opposite sides of said handle and fixed head unit, said unit and movable jaw having opposed gripping faces, and a pivot pin extending through aligned apertures in said legs and the handle and fixed head unit initially for being rotated in said apertures, the inside surface of said handle and fixed head uni-t adjacent to the corresponding aperture affording a bearing wall adjacent to one side of the unit for the pin, then a step'and an enlarged chamber off said step to the other side of the unit, a spring in said chamber and having opposite ends, one of said ends being engaged with said pin and the other of said ends being anchored to said handle and fixed head unit inside said chamber, and a key having a portion for engaging said pin to transmit rotation thereto in said apertures and accordingly store a bias in said spring for rotating the jaw and the gripping face thereon to a closed position with respect to the gripping face on said fixed head, and said key having a portion for engaging the adjacent leg of said movable jaw so as to lock said pin and movable jaw together for maintaining the bias stored in the spring.

2. A ply wrench according to claim 1 in which said key initially engages a slotted end of said pin for rotating the pin to store bias in the spring, and is forced further into said slotted end and into a notched portion of the adjacent leg thus to maintain the bias stored in the spring.

3. A ply wrench comprising a handle and fixed head unit, a movable jaw provided with legs overlapping opposite sides of said handle and fixed head unit, said unit and movable jaw having opposed gripping faces, and a pivot pin extending through aligned apertures in said legs and the handle and fixed head unit initially for being rotated in said apertures, the inside surface of said handle and fixed head unit adjacent to the corresponding aperture affording a bearing wall adjacent to one side of the unit for the pin, then a step and an enlarged chamber oflf said step to the other side of the unit, said pin having a longitudinal slot entering one of its ends, a convoluted spring around said pin in the enlarged chamber and having opposite ends, one of said ends being engaged with said pin in said slot and the other of said ends being anchored to said handle and fixed head unit inside said chamber, and a key having a portion for engaging an outer end of said pin to transmit rotation thereto in the apertures and accordingly store a bias in said spring for rotating the jaw and the gripping face therein to a closed position with respect to the gripping face on said fixed head, and said key having a portion for engaging the adjacent leg of,

7 i said movable jaw so as to lock said pin and movable jaw together for maintaining said bias stored in the spring.

4. A ply wrench comprising a handle and fixed head unit, a movable jaw provided with legs overlapping opposite sides of said handle and fixed head unit, said unit and movable jaw having opposed gripping faces, and a pivot pin including a headed end abutting the outside of one of said legs of the movable jaw and having a shank extending through aligned apertures in said legs and the handle and fixed head unit initially for being rotated in said apertures, the inside surface of said handle and fixed wall unit adjacent to the corresponding aperture affording a bearing wall adjacent to one side of the unit for the shank, then a step and an enlarged chamber off said step to the other side of the unit, the shank of said pin having a longitudinal slot in from its outer end, a convoluted spring around said shank in the enlarged chamber and having transversely and longitudinally disposed opposite ends, said transversely disposed end being engaged with said shank in said slot and the longitudinally disposed end being anchored to said handle and fixed head unit in a hole in the face of said step, a bearing washer on said shank and against the wall of said enlarged chamber 011 the far side of said spring from the step, and a key having a portion for engaging the outer end of said shank in the slot to transmit rotation to said shank in the apertures and accordingly store a bias in said opening for rotating the jaw and the gripping face thereon to a closed position with respect to the gripping face on said fixed head, and said key having a lateral extension face engaging the adjacent leg of said movable jaw in a notch in that leg off the corresponding aperture, thereby locking said pivot pin and movable jaw together for maintaining said bias stored in the spring.

5. A ply Wrench comprising a handle having a front edge and a longitudinal axis, a fixed head on said handle and having an edge provided with a substantially circular gripping face, said gripping face having a center, the center being located approximately on said longitudinal axis, and said gripping face beginning at about the top of said head and extending for at least about 50 degrees of arc to one side of the longitudinal axis, said head having a gripping edge extension between said substantially circular gripping face and the front edge of the handle and a downwardly and inwardly inclined edge portion leading from said extension to the front edge of the handle, a movable jaw having a forward end, an inside edge and a substantially straight gripping face extending backward from approximately said forward end, and a pivot interconnecting said jaw with said handle and fixed head for said jaw to rotate between closed and open positions relative to the head so that objects of various sizes may be gripped by said jaw and head, and said jaw having means for stopping rotation thereof about said pivot at the closed position, said circular gripping face being substantially bisected by a line passing through said center and normal to the line passing through said center and said pivot, said pivot being disposed on the other side of said longitudinal axis of the handle from said one side at about 0.3 to 0.9 the radial length of the substantially circular gripping face from said center and at about the same distance laterally from a given point located on the straight gripping face, said point being spaced from said inside edge of the jaw a distance about equal to half the length of a gap which is formed between said point and the beginning end of said circular gripping face in a substantially full open position of the jaw, a normal to said straight gripping face at said point intersecting said substantially circular gripping face at a succession of points throughout the length of said circular gripping face and in each instance passing substantially through the center of said circular gripping face when said movable jaw is rotated about the pivot, said gripping edge extension on the fixed head and an area of said straight gripping face ibehindsaidpoint-:in-ithelatter face being adapted to grip an object of relatively small size and to direct the gripping force substantially through said center when said movable jaw approaches the closed position with respect to said fixed head, and the forward end of said jaw in said closed position beingapproximately in the path of the line drawn through said center and the pivot and the forward end of the jaw forming a gap with said inclined portion of the head, the distance across said gap being at least equal to about one-half the gap which is formed between said point on the movable jaw and the beginning end of said circular gripping face in the substantially full open position of the jaw, whereby while the wrench is held by the handle, and while said downwardly and inwardly inclined portion of the head is placed against an object that is to be gripped, the forward end of said movable jaw is useful in the closed position of the jaw as a claw against the object for the jaw to be opened.

6. A ply wrench comprising a handle having a front edge and a longitudinal axis, a fixed head on said handle and having an edge provided with a substantially circular gripping face, said gripping face having a center, the center being located approximately on said longitudinal axis, and said gripping face beginning at about the top of said head and extending for about 70 degrees of arc to one side of the longitudinal axis, said head having a gripping edge extension between said substantially circular gripping face and the front edge of the handle and a downwardly and inwardly inclined edge portion leading from said extension to the front edge of the handle, a movable jaw having a forward end, an inside edge and a substantially straight gripping face extending backward from approximately said forward end, and a pivot interconnecting said jaw with said handle and fixed head for said jaw to rotate between closed and open positions relative to the head so that objects of various sizes may be gripped by said jaw and head, and said jaw having means for stopping rotation thereof about said pivot at the closed position, said circular gripping face being substantially bisected by a line passing through said center and normal to the line passing through said center and said pivot, said pivot being disposed on the other side of said longitudinal axis of the handle from said one side at about 0.6 the radial length of the substantially circular gripping face from said center and at about the same distance laterally from a given point located on the straight gripping face, said point being spaced from said inside edge of the jaw a distance about equal to half the length of a gap which is formed betwene said point and the beginning end of said circular gripping face in a substantially full open position of the jaw, a normal to said straight gripping face at said point intersecting said substantially circular gripping face at a succession of points throughout the length of said circular gripping face and in each instance passing substantially through the center of said circular gripping face when said movable jaw is rotated about the pivot, said gripping edge extension on the fixed head and an area of said straight gripping face behind said point in the latter face being adapted to grip an object of relatively small size and to direct the gripping force substantially through said center when said movable jaw approaches the closed position with respect to said fixed head, and the forward end of said jaw in said closed position being approximately in the path of the line drawn through said center and the pivot and the forward end of the jaw forming a gap with said inclined portion of the head, the distance across said gap being at least equal to about onehalf the gap which is formed between said point on the movable jaw and the beginning end of said circular gripping face in the substantially full open position of the jaw, whereby while the wrench is held by the handle, and while said downwardly and inwardly inclined portion of the head is placed against an object that is to be gripped,

- the; forward endof'said' movahlejaw-is-pseful in the closed position of the jaw as a claw against the object References Cited in the file of this patent for the jaw to be opened.

7. A ply wrench according to claim 5, in which said UNITED STATES PATENTS movable jaw is biased by spring means to rotate about 1 120 15 Holland 15, 1914 said pivot to said closed position and may be rotated to 5 1,421,206 GalBraith June 27 1922 the substantially full open position against the bias of 1,468,529 Vivarttas Sept 18, 1923 said spring means. 5

8. A ply wrench according to claim 5, in which said ggi'gg; g point on the straight gripping face of the movable jaw 2713280 Larson Jul 1955 is disposed about midway along the length of the straight 10 2742808 Haberle p 1956 gripping face.