US2725771A

US2725771A - Ratchet wrench

Info

Publication number: US2725771A
Application number: US457411A
Authority: US
Inventors: Harry I Arnold
Original assignee: Ingersoll Rand Co
Current assignee: Ingersoll Rand Co
Priority date: 1954-09-21
Filing date: 1954-09-21
Publication date: 1955-12-06
Anticipated expiration: 1972-12-06

Description

Dec. 6, 1955 H, ARNOLD 2,725,771

RATCHET WRENCH Filed Sept. 2l, 1954 32N 7 B482 v4 22 42 O2 68 38g .j 44 IOOFIG 2 e4 e2 64 j`5o R |02 68 y3 s` f2s 7o s WQ. 3MB

se# \6258 loe 96 s 2 Y? HIS ATTORNEY RATCHET WRENCH Harry I. Arnold, Athens, Pa., assigner to Ingersoll-Rand Company, New York, N. Y., ak corporation of New Jersey Application September 21, 1954, Serial No. 457,411

3 Claims. (Cl. 81-61) This invention relates to power tools, and more particularly to a driving mechanism for a portableratchet wrench.

ne object of the invention is to provide a motor driven ratchet wrench having a simplified arrangement of parts supported by a rigidly constructed casing adapted for use in poorly accessible places and which will prevent the motor from taking any thrust when used as a hand tool with the motor idle. p

Another object is to provide such a wrench with a driving mechanism which simply and efliciently transforms the rotary motion of the motor into reciprocating motion.

A further object is to provide such a wrench with driving connections which effectively translate the reciprocating motion into unidirectional rotary motion of the ratchet wrench socket.

Other objects will become apparent from the following description of the accompanying drawings, which illustrate a preferred embodiment of the invention in which similar numerals refer to similar parts.

Fig. l is a side elevation of the wrench, mostly in section, constructed in accordance with the practice of the invention,

Figs. 2, 3, 4 and 5 are transverse views taken along the lines 2 2, 3 3, 4-4 and 55, respectively, look-k ing in the direction indicated by the arrows, and

Fig. 6 is a perspective view of a detail of the invention.

Referring vto the drawings, and more particularly to Fig. l, the invention is shown as applied to a ratchet wrench'adapted to deliver torque to a ratchet socket 20, which is driven by a rotary motor (not shown) through a driving mechanism 22 driven thereby and operatively engaging driving connections 24 for rotating the socket. The whole mechanism is contained in a casing comprising a motor housing 26, a housing 28 and an extension 36 of the said housing.

Referring in greater detail to the construction of the wrench, the driving mechanism 22 consists of a spindle 32 directly connected toV a suitable non-reversible type electric or air-operated motor and axially mounted in the motor housing 26 by anti-friction bearings 34, only one of which is shown, and a driving rod or pitman 36 operatively connected to the spindle 32 for converting the rotary motion thereof into reciprocating motion.

For this purpose, the forward portion 38 of the spindle 32 is of increased diameter and has a transverse end face 4i? in which is formed an eccentrically located spherically-bottomed socket 42 to slidably receive the rearward ball-end 44 of the pitman 36. Holding the pitman in operative engagement with the spindle 32 is a retaining plate 46 having a suitable clearance slot 43 for straddling the pitman near the juncture of the ballend 44 and the central portion 50 thereof, the plate 46 being fastened in seating engagement with the end ited States Patent face 40 by a plurality of screws 52 threaded into the spindle.

This driving mechanism 22 is enclosed by the housing 28 which is screwed to the motor housing 26 to form a continuation thereof. Removably secured to the forward end of the housing' 28 is the housing extension 3d which supports the driving connections 24.

To this end, the housing 28 is provided with a concentric bore 54, at the bottom of which is a transverse surface 56 serving as a stop for the rearward portion 58 of the extensionv 30 and said portion 58 is of cylindrical shape to slidably fit the bore 54 and abut the surface 56. Retaining the extension in this position is a cap 6i) which has a clearance bore 62 encircling an adjacent elongated flat and narrow portion of the extension forming a spacer 64 having a width less thanv the diameter of the rearward portion 58 and which clamps the rearward portion between the housing surface 56 and a parallel transverse surface 66 on the cap 60 when the latter is screwed to the housing 28.

The extension 30 also comprises two ilat side plates 68 having the same width as the spacer 64 andwhich are held securely in parallel relation on opposite sides thereof by bolts and nuts, designated 70 and 72, respectively, and a pair of dowel pins 74 extending therethrough. The resulting sandwich construction provides a rigid structure for resisting the torsional stresses imposed upon it during operation of the wrench.

The forward ends of the side plates 68, which extend beyond the forward end of the spacer 64, are rounded to match the outside radius of the ratchet socket 2i) and have coaxial bores 76 for rotatably supporting trunnions 76 on the opposite ends of the socket. Axially located within the socket-20 is a hexagonal-shaped aperture 813 to accommodate a nut or the head of a bolt.

vThe socket 20 is driven by the driving connections 24 located in the extension 30 between the socket and the driving mechanism 22. For this purpose, the width ofthe spacer 64 is sulicientlyless than that of the side plates 68 to provide a suitably formed longitudinally extending slot 82p therebetween in parallel spaced relation to the axis of theA spindle 32 for slidably guiding a push rod 84 longitudinally disposed therein. The push rod together with an operatively connected pawl 86 constitute the driving connections 24 which convert the resulting reciprocating motion imparted by the pitrnanY operative engagement by an L-shaped retaining plate 92W;` having a Vsuitable clearance siot 94 for straddling 'the pitman 36 near the juncture of the ball-end 90 and the rod central portion 50, and which is secured in placevk by a laterally disposed screw 96 threaded into the push rod.

Also guiding the push rod 84 and serving as a pivot therefor to permit of both oscillatory and reciprocative movement, is a pin 93 extending transversely therethrough whose projecting end portions 100 slidably en- 1 gage longitudinally extending slots 102 in the side plates The forward end 104 of the push rod 84 is pivotally.V connected to the pawl 86 and is, therefore, of partly" cylindrical shape to slidably iit a correspondingly shaped socket 166 extending transversely through the rearward side of and adjacent the free end of the pawl. yThe for?"v i* ward side of the same end of the pawl 86 carries the c driving tip 108 which is appropriately shaped to engage'V Y the radial surfaces 110 of a series of ratchet teeth 111 j on Athe periphery of the medial portion 112 of the socket 2? for rotating the socket.

Supporting and guiding the pawl 86 for combined reciprocatve and oscillatory movement, is a transversely extending pin -114 slidably.ttinga-.laterallydisposed slot 116 in the opposite end of the pawl. The end portions 118 'of `the pin 114 are Vof reduced4 diameter4 and are seated in the side plates68..

A pre-tensioned coil spring 120 inclined with respect to the axis of the spindle 32 `provides a resultant force to constantly urge the pawl 86 to a `position for engagement with the ratchet teeth 111 and in which position the slot 116 seats against,the.pin,114. To this end, a forward hooked end'121 of the spring 1,20 is mounted on a pin 122 spanning `a slot, l24 .at the rearward side of the'pawl, while thefrearward hooked end 125 isv anchored on atransverse pin 126 positioned across a suitably located blind hole 128 in the spacer 64.

In order to prevent reverse rotation :of thesocket .20, a plunger type detent 130 `slidablymounted in a longitudinally extending'blind hole-132in `the forward part of the spacer 64 projects into thepath .of the ratchet teeth 111 and has a suitably;` shaped tip 134 for locking engagement with said teeth.r Constantly urging this engagement is a pre-compressed coil spring 136 seated at the bottom of the hole 132 and bearing against the rearward end of the detent 130.

In operation, the wrench is positioned by the operator with the socket in engagement with a threaded element to be tightened and the motor is started. This rotates the spindle 32 which, through the pitman 36, causes the push rod 84 and the pawl 86 to reciprocate and oscillate rapidly, thereby intermittently vrotating the socket 20 until the threaded element has-been suiciently tightened. In instances where it may be desirable to tighten such an element in excess of the torque supplied by the motor, the wrench can be manually turned about the socket axis to drive the threaded element home; the detent 130 serving to tixedly lock 4the socket 20 in the wrench. It will be apparent that the reverse operation of initially loosening a threaded element by the manual manipulation of the wrench and the subsequent complete removal of the element by motor power, can easily be accomplished by inverting the wrench to reverse the` position of the socket on the element, thereby eliminating the necessity of using a more expensive reversible-type motor.

Thus it will be seen, that a dual purpose wrench of simple and rugged construction is provided and that it is well adapted for the rapid tightening and loosening of nuts or bolts in poorly accessible places and that it will resist distortion when used as a hand tool. Moreover, the wrench includes a simple driving mechanism incorporating few parts having low friction joints for efficiently and economically converting the rotary power of the motor through the combined reciprocatve and oscillatory motion of the driving connections into the intermittent unidirectional torque of the wrench socket.

I claim:

1. In a power driven tool, the combination of a rotary spindle having an eccentrically disposed socket, a double ball-ended pitman having one ball end slidably coning a push rod longitudinally disposed in substantially parallel spaced relation to the axis of said spindle and slidable in the tool for reciprocatve and oscillatory movement, one end of said push rod having a socket to slidably receive the other ball end of said pitman and the other end being of partly cylindrical shape, a rotatable ratchet member for engaging a work piece, a pawl having a socket to slidably receive the said other end of said push rod and being slidably mounted for reciprocatve and oscillatory movement to rotate the ratchet member, and a spring constantly urging engagement of the pawl with said ratchet member.

2. In a portable power driven tool, the combination of a casing, a rotary spindle in the casing having a partlyspherical eccentrically disposed socket, an elongated at and narrow portion of said casing forming an extension thereof, a, rotatable Aratchet toothed member transversely mounted on the extension in spaced relation tosaid spindle for engaging a work piece, a pawl slidably mounted in the extension for reciprocatve and oscillatory movement, one end of said pawl being adapted to engage the teeth of said ratchet member and having a cylindrical-segment shaped socket, a push rod longitudinally disposed in said casing extension in substantially parallel spaced relation to the axis of said spindle and slidably guided for ,reciprocatve and oscillatory movement, one end of said push rod slidably litting the socket in said pawl and the other end having a partlyspherical socket, a pitman having partlyspherical ends slidable in the spindle and push rod sockets, respectively, a spring constantly urging the pawl into engagement with the teeth on said ratchet member, a detent slidably mounted in the extension to engage said teeth, and a spring constantly urging the detent into engagement with said teeth.

3. A driving mechanism for a portable power driven toolV having a casing, a rotatable ratchet toothed member in the casing, reciprocable and oscillatable driving means for rotatably advancing the ratchet member, comprising a rotary spindle axially mounted in the casing in longitudinally spaced relation to said driving means and having a spherically-bottomed eccentrically disposed socket, and a double spherical-ended pitman having its rearward end slidably tting the socket in the spindle and its forward end operatively connected to the driving means for translating the rotary motion of the spindle into the reciprocatve motion of said driving means.

References Cited inthe tile of this patent UNIlIED STATES PATENTS 757,137 Munro Apr. l2, 1904 953,233 Robinson Mar. 29, 1910 1,578,268 De Lavaud Mar. 30, 1926 2,119,968 Sha June 7, 1938 2,264,012 Wasson Nov. 25, 1941 2,491,624 Shat Dec. 20, 1949