US2719446A - Ratchet wrench - Google Patents

Description

W. B. FORD RATCHET WRENCH 2 Sheets-Sheet l Filed May 25, 1953 mt., 4v 4 W B. FORD RATCHET WRENCH Filed May 25, 1953 2 Sheets-Smet 2 United States Patent O RATCHET WRENCH William B. Ford, Bryan, Ohio, assignor to Aro Equip-s This invention relates to a ratchet wrench of the openend type which has a head that may be used on a hexagonshaped nut, a bolt, a cap screw head, or a tubing nut, which is accessible only from the side, to impart rotation thereto either continuously or intermittently in as little as one-twelfth of a revolution, or by swinging motion of the tool to tighten through an are of from near zero to the index of the head (one-twelfth of a revolution), employing for this purpose a pair of nut-engaging cams or rockers wherein notches in the sides of the cams engage the nut when the head is oscillated slightly more than one-twelfth revolution.

This invention embodies certain improvements and changes over the ratchet wrench disclosed by my prior application Serial No. 334,539, filed February 2, 1953.

' One object of the invention is to provide an open-end ratchet wrench of this general character which may be power operated and which has a relatively small thickness so that it eliminates the necessity of considerable head room to work on a nut or bolt as required by many types of power wrenches.

Another object is to provide a wrench which is adapted for power operation as by means of a pneumatic motor, the wrench comprising a wrench head which is oscillatably mounted in a frame attached to the motor and the frame including mechanism for translating the rotations of the motor shaft into oscillations of the wrench head.

A further object is to provide a n'ovel wrench head which may be slipped edgewise over a nut and when in operating position has a circular part clearing the corners of the nut, the circumferential extent of which is a greater than 180 degrees so that it substantially confines the nut against slipping of the wrench therefrom during operation of the wrench.

Still a further object is to provide a C-shaped wrench head which is oscillatably mounted in a frame of the tool and is provided with one or more nut-engaging cams or rockers having notches therein to engage the nut and to rotate it when the wrench head is oscillated in one direction, the cams being rotatable in the wrench head from a xed position to a rotated position of compression against retaining spring means, so that the notch surface of the cams rotates from a position of engagement with the nut to one of clearance in ratcheting fashion when the wrench head is oscillated.

An additional object is to provide a relatively simple C-shaped wrench head with relatively simple cam and rocker arrangements in conjunction therewith, and a gear sector, idler gear, and rack arrangement for changing reciprocations of the rack into oscillations of the wrench head, the rack in turn being reciprocated by a cam on the motor shaft.

Another additional object is to provide a holding pawl, having a serrated surface with a radius of curvature slightly larger than the outer radius of the nut head so as to clear the nut corners, the nut being centered by the cams when turned and held thereby just clear of the serrations, the holding pawl serving as a stop against the ICC nut head during some types of operations and as a holding means to prevent reverse rotation of the nut during other types of operations.

With these and other objects in view, my invention consists in the construction, arrangement, and combination of the various parts of my ratchet wrench, whereby the objects contemplated are attained, as hereinafter more fully set forth, pointed out in my claims and illustrated in the accompanying drawings, wherein:

Figure l is a plan view of a ratchet wrench embodying my present invention with a cover plate removed and part of the housing and other elements shown in section.

Figure 2 is a detail sectional view on the line 2-2 of Figure 1.

Figure 3 is a detail sectional view on the line 3--3 of Figure 1, and shows the motor for the wrench partially in side elevation.

Figure 4 is an enlarged view similar to the left-hand end of Figure l, with the wrench head shown in section, and illustrating the cooperation of one notched cam in each of two pair thereof with two opposite corners of a nut.

Figure 5 is a similar view showing the nut turned 30 degrees clockwise.

Figure 6 is a similar View showing the wrench head being oscillated in the opposite direction, and the notched cams ratcheting over the corners of the nut.

Figure 7 shows the nal position for each of the other notched cams to engage the corners of the nut just before another reciprocation clockwise to rotate the nut another 30 degrees.

Figure 8 is a perspective view of a notched cam and its spring and keeper pin as used in the wrench head of my ratchet wrench.

On the accompanying drawings I have used the referenee numeral 10 to indicate a motor for operating the wrench which motor may be pneumatically powered and provided with a throttle valve 12 and a throttle lever 14 in the usual manner. The shaft of the motor is indicated at 16.

I provide a body or frame 18 which is partially fiat and partially circular as shown in Figure 3. The circular part is engaged with a ange 20 of the motor 10 by a retainer nut 22 so that the frame may be readily connected and disconnected in relation to the motor. `The frame 18 is provided with a hollow space therein for an idler gear 24 having teeth 2S, a rack 26 having teeth 27, and portions of a Gashaped wrench head 2S. A stud 29 having reduced ends is provided on which the gear 24 rotates.

The wrench head 28, as shown in Figure l, is provided with a circumference and an inner cylindrical surface 32. The circumference 30 has a projection 34 as shown in Figure 2 which interts in a corresponding arc-shaped groove 33 of the frame 18 for permitting rotation or oscillation of the wrench head relative thereto. A cover plate 36 retains the wrench head in position and also covers the cavity in the frame in which the elements 24 and 26 are mounted. The projection 34 of the wrench head is provided with gear teeth meshing with the idler gear 24, and the teeth of the idler gear 24 also mesh with those of the rack 26 so that any oscillations imparted to the rack will oscillate the wrench head. For imparting such oscillations thereto, I provide a cam 38 keyed at 4l) to a sleeve 42 mounted on the motor shaft 16 and cooperating with a roller 44 carried by the rack. To retain the roller in contact with the cam 3S, I provide a spring 46 interposed between a socket 48 in the frame 18 and a socket 50 in a head 52 of the journal pin 54 provided for the roller 44, all as shown in Figure l.

With specific reference to the @shaped wrench head 28, it is provided with opposite parallel jaws 56 and 58. The distance between these jaws is just slightly greater than the smal-l diameter of a hexagon nut 59 as shown in Figure 7. The cylindrical surface 32 is just large enough to receive the nut or has a radius substantially equal to the radius of the corner of the nut.

I` provide two pair of notched cams, 60 and 60a, and 61 and' 61a, which are rotatably mounted in sockets 62, in the wrench head 28 along axes parallel to the longitudinal axis of the nut. The sockets are exposed at the inner surface of the wrench head over an angle of arc substantially less than 180. The cams are retained in position by the wrench head 28, and are normally seated by means of springs 64 which bias keeper pins 65 toward the cams, the keeper pins seating in recesses 66 in the cams as shown in Figure 8. Therefore, the notched cams or rockers can be forced to rotate in their sockets against the bias of the springs 64 as shown in Figure 6, for instance ( cams 60a and 61a), when the wrench head is oscillated in a return or counterclockwise direction.

Also in connection with the wrench head, I provide an L-shaped holding pawl 68 having a serrated engagingsurface 69 with a radius of curvature just large enough to clear the` corners of the nut when the nut is held in a centered position by the cams.

Practical operation In operation, my ratchet wrench may be placed against a bolt or cap screw head 59, as in Figure l, and the holding pawl 68 is then forced against one or two corners of the nut, in which position the serrations. thereof act as a stop to prevent rotation of the nut in a direction opposite that desired. The notched cams or rockers, when they become operative to engage and rotate the nut, will serve to center the nut so as to provide clearance between the nut corners and the holding pawl, whereupon actuation of the motor drive will effect oscillation of the wrench head and rotation of the nut without interference therewith by the serrations of the pawl.

Assuming a starting position such as shown in Figure 4, the angle A between the notched cams 60 and 60a is substantially 30 degrees for my ratchet wrench when designed for a hexagonal nut head in order to rotate the nut in increments of one-twelfth of a revolution, as will hereinafter appear. It will be apparent that if the C- shaped wrench head 2.8 in Figure 4 is now rotated clockwise, the notched cams 60a and 61a will have no effect, but the cams 60 and 61 will engage the upper and lower corners respectively of the nut 59 and rotate the nut in a clockwise direction through an arc of 30 degrees to a final position as shown in Figure 5, Whereupon the wrench head has reached the limit of its clockwise rotation and is ready to rotate counterclockwise.

Figure 6 shows about one-half of the return or counter-clockwise rotation completed. The notched cams 60a and 61a' are now ratcheting across the corners of the nut above referred to, and are shown rotated in a counter-clockwise direction against the bias of springs 64. At the same time, the serrations of the holding pawl will ac t to grip the adjacent corner of the nut as the manual pressure exerted by the operator serves to move the wrench head forwardly against the nut'. Normally, the nut and wrench head will have some degree of free relative movement, one within the other. When the gripping rockers are operatively effective to turn the nut, the latter will be centered within the head, permitting the corners of the nut to clear the serrated surface of the holding pawl. As the rockers ratchet back across the corner of the nut during a return oscillation, the manual force exerted by the operator will serve to eccentrically position the nut and head, relative to each other, thereby permitting the holding pawl to move forwardly to engage and grip an adjacent corner of the nut and preclude reverse rotation thereof. In this manner, counter-clockwise rotation of the nut as the rockers ratchet back is prevented.

Further rotation of the Wrench head will permit the springs 68 to return the cams 60a and 61a to the normal position of Figure 7 Where cams 60a and 61a now engage opposite corners of the nut for effecting the next 30 degrees of rotation as the wrench rotates in` a clockwise direction.

Similarly, during the next counter-clockwise reciprocation of the wrench head, the cams 60 and 61 will ratchet over the next corners of the nut and assume the position of Figure 4 for rotating those corners. The cycle will be repeated with the cam pairs 60-61 and 60a-61a alternately engaging the nut corners.

With a wrench of the character shown, the motor 10 may be used for rotating the nut 59 until it stalls the motor whereupon the length of the frame 18 plus the motor 10 serves as a handle of suflicient leverage to tighten the nut by hand, the gearing being locked due to coming to the end of the throw such as the position shown in Figure l with the roller 44 at the bottom of the cam surface 38, or the wrench can be used for hand tightening at any position on the cam rise in confined areas for small degrees of motion.

To rotate the nut in a counter-clockwise direction, it is merely necessary to turn the complete wrench including the frame 18 over. The wrench head can then be applied to the nut and the tool used as a hand lever for loosening the nut after which the motor may be energized for removing the nut. I have illustrated one size of wrench head 28 and it will be obvious that it fits but one size of nut. It may, of course, be made in various sizes and each Wrench, being readily attachable and detachable relative to the motor 10, minimizes wrench changing. This is no disadvantage in mass production, however,` as it would be the usual practice for one workman to operate. on only the size of nut which his wrench will t.

Some changes may be made in the construction and arrangement of the parts of my ratchet wrench without departing from the real spirit and purpose of my invention, and it is my intention to cover by my claims any modified forms of structure or use of mechanical equivalents which may be reasonably included within their scope.

I claim as my invention:

l. In a ratchet wrench of the character described, a C-shaped wrench head, a frame oscillatably supporting said head, means for oscillating said head relative to said frame, said head having opposite jaws of sufficient spread to receive the small diameter of a nut, inwardly of said jaws a surface of suticient size to receive the corners of the nut and of sufficient extent to substantially coniine the nut therein during oscillations of said wrench head, two pairs of notched cams rotatably mounted in said head for engaging opposite corners of the nut, spring means disposed in said head and biased toward said cams to hold the cams in a normally lixed position, said cams projecting through said inwardly disposed surface of said head toward the nut to engage the corners thereof and rotate it when said head is oscillated around the nut in one direction, said cams rotating and ratcheting over the corners of the nut when said head is oscillated around the nut in the opposite direction, and a holding pawl having a serrated engaging surface with a radius of curvature slightly larger than the outer radius of'the nut head so as to clear the nut corners, the nut being centered by the cams when turned and held thereby just clear of the serrations.

2. In a ratchet wrench of the character described, a C-shaped wrench head, a frame oscillatably supporting said head, means for oscillating said head relative to said frame, said head having opposite jaws of sucient spread to receive the small diameter of a nut, inwardly of said jaws a surface of sufcient size to receive the corners of the nut and of sufcient extent to substantially conne the nut therein during oscillations of said wrench head, two pairs of notched cams rotatably mounted in said head for engaging opposite corners of the nut, spring means disposed in said head and biased toward said cams to hold the cams in a normally fixed position, said cams projecting through said inwardly disposed surface of said head toward the nut to engage the corners thereof and rotate it when said head is oscillated around the nut in one direction, said cams rotating and ratcheting over the corners of the nut when said head is oscillated around the nut in the opposite direction, and a holding pawl having a serrated engaging surface with a radius of curvature slightly larger than the outer radius of the nut head so as to clear the nut corners, the nut being centered by the cams when turned and held thereby just clear of the serrations, said serrated engaging surface having a circumferential extent greater than the angle subtended by two adjacent nut corners.

3. In a ratchet wrench of the character described, a C-shaped wrench head, a frame oscillatably supporting said head, means for oscillating said head relative to said frame, said head having opposite jaws of sufficient spread to receive the small diameter of a nut, inwardly of said jaws a surface of sufficient size to receive the corners of the nut and of sufficient extent to substantially confine the nut therein during oscillations of said wrench head, two pairs of notched cams rotatably mounted in said head for engaging opposite corners of the nut, spring means disposed in said head and biased toward said cams to hold the cams in a normally fixed position, whereby one of each of said pairs of cams simultaneously engages an opposite corner of the nut and effects rotation of the nut when the head is oscillated in the one direction, each of the remaining cams of said pairs being then ineffective, each of said first engaging cams ratcheting across the corners of the nut by rotation against their respective spring means when the head is oscillated in the other direction, and each of the other of said pairs of cams effectively engaging and ratcheting over the corners of the nut during alternate cycles of oscillation.

4. In a ratchet Wrench of the character described, a C-shaped wrench head, a frame oscillatably supporting said head, means for oscillating said head relative to said frame, said head having opposite jaws of sufficient spread to receive the small diameter of a nut, a first partial cylindrical surface of sufficient size to receive the corners of the nut and a second partial cylindrical surface inwardly and of greater radius of curvature than said first, the combined circumferential extent of said cylindrical surfaces being greater than 180 degrees to substantially confine the nut therein during oscillations of said wrench head, two pairs of notched cams rotatably mounted in said head for engaging opposite corners of the nut, spring means disposed in said head and biased toward said cams to hold the cams in a normally fixed position, whereby one of each of said pairs of cams simultaneously engages an opposite corner of the nut and effects rotation of the nut when the head is oscillated in the one direction, each of the remaining cams of said pairs being then ineffective, each of said first engaging cams ratcheting across the corners of the nut by rotation against their respective spring means when the head is oscillated in the other direction, and each of the other of said pairs of cams effectively engaging and ratcheting over the corners of the nut during alternate cycles of oscillation.

5. In a ratchet wrench of the character described, a C-shaped wrench head, a frame oscillatably supporting said head, means for oscillating said head relative to said frame, said head having opposite jaws of sufficient spread to receive the small diameter of a nut, a first partial cylindrical surface of sufficient size to receive the corners of the nut and a second partial cylindrical surface inwardly and of greater radius of curvature than said first, the combined circumferential extent of said cylindrical surfaces being greater than 180 degrees to substantially confine the nut therein during oscillations of said wrench head, two pairs of notched cams rotatably mounted in said head for engaging opposite corners of the nut, spring means disposed in said head and biased toward said cams to hold the cams in a normally fixed position, said cams projecting through said first surface inwardly ltoward the nut to engage the corners vthereof and rotate it when said head is oscillated around the nut in one direction, and said cams being rotated by the nut to expose the notched surfaces thereof in a ratcheting fashion when said head is oscillated around the nut in the opposite direction.

6. In a ratchet wrench of the character described, a C-shaped wrench head, a frame oscilla'tably supporting said head, means for oscillating said head relative to said frame, said head having opposite jaws of sufficient spread to receive the small diameter of a nut, a first partial cylindrical surface of sufficient size to receive the corners of the nut and a second partial cylindrical surface inwardly and of greater radius of curvature than said first, the combined circumferential extent of said. cylindrical surfaces being greater than degrees to substantially confine the nut therein during oscillations of said wrench head, two pairs of notched cams rotatably mounted in said head for engaging opposite corners of the nut, spring means disposed in said head and biased toward said cams to hold the cams in a normally fixed position, said wrench head having cylindrical sockets for each of said said cams, said sockets being exposed at said first partial cylindrical surface, said cams projecting through said first surface inwardly toward the nut to engage the corners thereof and rotate it when said head is oscillated around the nut in one direction, and said cams being rotated by the nut to expose the notched surfaces thereof in a ratcheting fashion when said head is oscillated around the nut in the opposite direction.

7. In a ratchet wrench of the character described, a C-shaped wrench head, a frame oscillatably supporting said head,` means for oscillating said head relative to said frame, said head having opposite jaws of sufficient spread to receive the small diameter of a nut, a first partial cylindrical surface of sufficient size to receive the corners of the nut and a second partial cylindrical surface inwardly and of greater radius of curvature than said first, the combined circumferential extent of said cylindrical surfaces being greater than 180 degrees to substantially confine the nut therein during oscillations of said Wrench head, two pairs of notched cams rotatably mounted in said head for engaging opposite corners of the nut, spring means disposed in said head and biased toward said cams to hold the cams in a normally fixed position, said wrench head having cylindrical sockets for each of said cams, said sockets being exposed at said first partial cylindrical surface over an angle of arc substantially less than 180 degrees so that said cams are retained in position by portions of the head, said cams projecting through said first surface inwardly toward the nut to engage the corners thereof and rotate it when said head is oscillated around the nut in one direction, and said cams being rotated by the nut to expose the notched surfaces thereof in a ratcheting fashion when said head is oscillated around the nut in the opposite direction.

8. In a ratchet wrench of the character described, a C-shaped wrench head, a frame oscillatably supporting said head, means for oscillating said head relative to said frame, said head having opposite jaws of sufficient spread to receive the small diameter of a nut, a first partial cylindrical surface of sufficient size to receive the corners of the nut and a second partial cylindrical surface inwardly and of greater radius of curvature than said first, the combined circumferential extent of said cylindrical surfaces being greater than 180 degrees to substantially confine the nut therein during oscillations of said wrench head, two pairs of notched cams rotatably mounted in said head along axes parallel to the longitudinal axis of the nut for engaging opposite corners of the nut, said wrench head having cylindrical sockets for each of said cams, said sockets being exposed at said first partial cylindrical surface over an angle of arc substantially less than 180 degrees so that said cams are retained in position by portions of the head, said cams projecting through `said iirst surface inwardly toward the nut to engage the corners thereof and rotate it when said head is" oscillated around the nut, and spring means mounted in the head and biased toward said cams to hold the cams in a normally fixed position with respect to rotation about the said axes.

9..,In a ratchet wrench of the character described, a llfshaped wrench head, a frame oscillatably supporting said head, means for oscillating said head relative to said frame, said head having opposite jaws of sufficient spread to receive the small diameter of a nut, inwardly of said jaws a surface of suliicient size to receive the corners of the nut and of suficient extent to substantially cjon'fi'ne the nut therein during oscillations of said wrench head, two pairs of notched cams rotatably mounted in said head for engaging opposite corners of the nut, springrneans disposed in said head and biased toward said earns to hold the cams in a normally fixed position, said cams projecting through said inwardly disposed'surface of said head toward the nut to engage the corners thereof and rotate it when said head is oscillated around the nut in one direction, said cams rotating and ratcheting over the corners of the nut when said head is oscillated around the nut in the opposite direction.

v 10. In a ratchet wrench of the charac-ter described, a C-shaped wrench head, a frame oscillatably supporting said head, means for oscillating said head relative to said frame, said head having opposite jaws of sufficient ,spread to receive the small diameter of a nut, Vinwardly CFI of said jaws a surface of sufficient size to receive the corners of the nut and of sufiicient extent to .substantially confine the nut therein during oscillations of said wrench head, two pairs of notched cams rotatably mounted'in said head for engaging opposite corners of the nut, spring means disposed in said head/and biased toward said cams to hold the cams in a normally fixed position, said cams projecting through said inwardly disposed surface of said head toward the nut to engage the corners thereof, one of each of said pair of cams engaging diametrically opposite corners of the nut and eflecting rotation of the nut when the head is oscillated in the one direction and ratcheting across the corners of the nut by rotation against their respective spring means when the head is oscillated in the other direction, each of the other of said pairs of cams eifectively engaging and ratcheting over the corners of the nut during alternate cycles o'f'oscilla-4 tion.

References Cited in the iile of this patent UNITED STATES PATENTS Sharil v. a Dec. 20, 1949

Images