US2752810A

US2752810A - Power operated ratchet wrench

Info

Publication number: US2752810A
Application number: US457402A
Authority: US
Inventors: Harold C Reynolds
Original assignee: Ingersoll Rand Co
Current assignee: Ingersoll Rand Co
Priority date: 1954-09-21
Filing date: 1954-09-21
Publication date: 1956-07-03
Anticipated expiration: 1973-07-03

Description

y 3, 1956 H. c. REYNOLDS POWER OPERATED RATCHET WRENCH Filed Sept. 21, 1954 S 0 W H 8 4 8 O G/TWG 5 TO N m m Y m m W w 8 m F A 7 M C S O DY m 2 LB I O 3 M G H 6 2 F 1 w m ROTATED BY NON- REVERSIBLE 32 ROTARY MOTOR TUWER UlPERATED RATEIEET WRENCH Harold (C. Reynolds, Athens, Pa, assignor to Ingersoll- Rand Company, New York, N. Y., a corporation of New Jersey Application September 21, 1954, Serial No. 457,402

l tlllaims. (Cl. til-58.1)

This invention relates to power tools, and more particularly to a driving connection for a portable ratchet wrench.

One object of the invention is to provide an improved 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 resist the tendency of twisting when used as a hand tool when the motor is idle.

Another object is to provide such a wrench having a driving mechanism which produces reciprocating motion with a driving connection which simply and efiiciently transforms the reciprocating motion into unidirectional rotary motion of the 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 and 4 are transverse views taken along the lines 2-2, 3-3 and 4-4, of Fig. 1, respectively, looking in the direction indicated by the arrows, and

Pig. 5 is a perspective view of a detail of the invention.

Referring to Fig. 1 of the drawings, the invention is shown as applied to a ratchet wrench adapted to deliver torque to a ratchet socket 2%, which is driven by a motor (not shown) through a driving mechanism 22 operatively engaging a driving connection 24 for rotating the socket. The whole mechanism is contained in a casing comprising an elongated motor housing 26, a housing 28 and an extension 30 of the said housing.

Referring in greater detail to the construction of the wrench, the driving mechanism 22 consists of a rotary spindle 32 (only a part of which is shown) directly connected to be driven by a suitable non-reversible type electric or air-operated rotary motor (not shown) and mounted axially in the motor housing 26 by anti-friction bearings Curly one of the bearings 34 is shown, and a driving rod or pitman as is operatively connected to the spindie 32 for converting the rotary motion thereof into reciprocating motion of the driving connection 24.

The spindle 32 carries a flange 38 and in the forward end 40 thereof is an eccentrically located sphericallybottomed socket 42 to receive a ball-end 44 of the pitman 36. The pitman 36 is held in operative engagement with the spindle 32 by a plate 46 having a suitable clearance slot 4-3 to enable the plate to straddle the pitman near the juncture of the ball-end 44 and the body 50 thereof, the plate 46 being fastened in seating engagement with the end all by screws 52 threaded into the flange 38.

The mechanism thus far described is enclosed by the housing 28 which is screwed to the motor housing 26 at one end and at its other end to the extension 30 which supports the driving connection 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 dtates Patent 0 ice stop for the rearward portion 58 of the extension 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 69 which has a bore 62 encircling an adjacent elongated fiat and narrow portion of the extension forming a spacer 64 of a width smaller than the diameter of the rearward portion 58 and of uniform thickness throughout its length. The cap 69 clamps the portion 58 between the housing surface 56 and a transverse surface 66 on the cap 60.

The extension 30 also comprises two flat side plates 68 of slightly greater width than the spacer 64 for added stiffness and which are held securely against the opposed sides of the spacer by a pair of bolts and nuts, designated 70 and '72, respectively. The resulting sandwich construc tion provides a rigid structure for resisting the bending stresses imposed upon it during operation of the wrench.

The forward ends of the side plates 68, which extend beyond the corresponding end of the spacer 64, are rounded to match the outside radius of the ratchet socket 2d and have coaxial bores '74 to rotatably support trunnions 76 on the opposite ends of the socket. Axially located within the socket 2t and the trunnions is a hexagonal-shaped aperture '78 to accommodate a work piece, such as a not or the head of a bolt.

The socket 263 is driven by the driving connection 24 located in the extension 30 between the socket and the driving mechanism 22. For this purpose, the width of the spacer is sumciently less than that of the side plates 68 to provide a longitudinally extending guideway 80 between the plates and in parallel spaced relation to the axis of the spindle 32 for slidably guiding an elongated driving pawl 82 longitudinally disposed therein.

The driving pawl constitutes the driving connection 24 which converts the reciprocating motion of the pitman 36 into unidirectional rotary motion of the ratchet socket 20. To accomplish this, the pawl 82 has a sphericallybottorned socket 84 at its rearward end to receive a ballend as of the pitman 36. The pitman and the pawl 82 are held in operative engagement with each other by an L-shaped plate 8% having a suitable slot to enable the plate to straddle the pitman 36 near the juncture of the ball-end 86 and the body 50 of the rod for retaining the said ball-end in the socket 84. The plate 88 is secured in place by a screw 92. threaded into the pawl $2.

The rearward outside surface 94 of the driving pawl 82 is shaped to match the curvature of the surface 95 of the bore 62 in the cap 60, which serves as a bearing for the pawl to resist the thrust imposed by the pitman 36 as the pitman causes the pawl to reciprocate in the guideway 80.

The forward end of the driving pawl 82 constitutes a driving tip 96 and is appropriately shaped to conform to the shape of the surfaces 98 of a series of ratchet teeth Mill on the periphery of the medial portion 102 of the socket 2% for rotating the socket. As the pawl 82 travels forward in the guideway 80, the tip 96 is forced to follow a portion of the circular path traced by the teeth Mill and the pawl is caused to swing outwardly about the sur face 95 acting as a fulcrum therefor. The rearward inside surface 193 of the guideway 80 is accordingly sloped outwardly toward the guideway to provide free movement of the swinging pawl 82.

immediately rearwardly of the tip 96 and on the inner side of the pawl 32 is a lateral extension 104 to which is anchored a pre-tensioned coil spring 106 which constantly urges the pawl into engagement with the ratchet teeth res and thereby swings the pawl inwardly on its rearward stroke about the surface 95 to complete the resulting oscillatory movement of said pawl. The forward hooked end 108 of the spring 106 is mounted on a pin 110 spanning a slot 112 in the extension 104, while the tighten the work piece.

3 rearward hooked end 114 is anchored on a pin 116 posi tioned across a hole 118 located in the rearward portion of the spacer 64. To further insure continuous engagement of the pawl 82 and the teeth 100, the

pins

110 and 116 are located such Wise that the spring 106 inclines outwardly from the pin 116 toward the pawl 82.

In order to prevent retrograde rotation of the socket 20, a lock pawl 120 having a bore 122 at its rearward end slidably fitting a pin 124 located between the spacer 64 and the socket 20, swings into the path of the ratchet teeth 100 and carries at its forward end a suitably shaped tip 126 for locking engagement with said teeth. The end portions (not shown) of the pin 124 are fixedly mounted in the side plates 68. A pre-compressed coil spring 128 holds the pawl 120 in engagement with the teeth 100 and its ends are seated at the bottoms of

blind holes

130 and 132, located in the forward end of the spacer 64 and in the rearward side of the lock pawl 120, respectively.

In operation, the wrench is positioned to place the socket 20 in engagement with a work piece and the motor is then started. The spindle 32, being rotated thereby, will impart, through the pitman 36, a reciprocatory motion to the pawl 82, which will also describe an oscillatory movement imparted by the spring and by the socket accordingly as the pawl follows the path of movement of the teeth 100 during the working stroke of the pawl to In instances where it may be desirable to tighten such a work piece in excess of the torque supplied by the motor, the wrench can be manually turned about the socket axis to drive the work piece home; the lock pawl 120 serving to fixedly lock the socket 20 in the wrench. It will be apparent that the reverse operation of initially loosening a work piece by force applied manually to the wrench and the subsequent complete removal of the work piece by motor power, can easily be accomplished by inverting the wrench to reverse the position of the socket on the work piece, thereby eliminating the need for a comparatively costly reversibletype 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 connection for efliciently and economically translating the reciprocating motion imparted by the driving mechanism into unidirectional rotary motion of the wrench socket.

I claim:

1. In a power driven tool, a casing having a guideway, a fulcrum on the guideway, a rotatable tool member in the casing, ratchet teeth on the tool member, a pawl bearing on the fulcrum and reciprocable in the guideway for engagement with the ratchet teeth to rotate the tool member and turnable on the fulcrum to follow the arc of rotation described by the teeth, and a spring swingably connected to the casing and the pawl constantly tending to turn said pawl about the fulcrum to a position for engagement with the teeth.

2. In a power driven tool, a casing having a longitudinally extending guideway, a rotatable tool member in the forward end of the casing adjacent the guideway, ratchet teeth on the tool member, a fulcrum on the guideway remote from the tool member, a pawl bearing on the fulcrum and longitudinally disposed in the guideway and reciprocable therein for engagement with the ratchet teeth to rotate the tool member, said pawl being swingable about the fulcrum to follow the circular path of the teeth, and a spring swingably connected to the casing and the pawl adjacent its forward end to constantly urge said pawl against the ratchet teeth..

3. In a power driven tool, an elongated casing having a rotary spindle mounted axially therein and a longitudinally extending guideway in parallel spaced relation to said spindle axis, a rotatable tool member in the forward end of the casing at one end of the guideway, ratchet teeth on the tool member, a fulcrum on the guideway at the other end thereof, an elongated driving pawl bearing on the fulcrum and reciprocable in the guideway for engagement with the ratchet teeth to rotate the tool member and rockable outwardly about the fulcrum on its forward stroke, and a pre-tensioned spring having its forward end swingably connected to the inner forward portion of the pawl and its rearward end swingably connected to the casing such that the spring inclines outwardly toward said pawl forward portion to rock the pawl inwardly about the fulcrum on its rearward stroke to a position for engagement with the teeth.

4. In a power driven tool having an elongated casing and driving means therein, the combination of a longitudinally extending guideway in the casing, a fulcrum on the guideway at the rearward end thereof, a rotatable tool member in the casing at the forward end of the guideway, ratchet teeth on the tool member, a driving connection between the tool member and the driving means and including an elongated driving pawl having its rearward outside surface bearing on the fulcrum and a driving tip at its forward end adapted to engage the ratchet teeth, said pawl being reciprocable in the guideway for engaging the driving tip with the ratchet teeth to rotate the tool member and its rearward outside surface swingable about the fulcrum such that the tip follows the circular path of the teeth, a spring having its forward end swingably connected to the pawl adjacent the tip and its rearward end swingably connected to the casing adjacent the rearward end of the pawl constantly tending to swing said pawl about the fulcrum to engage the tip with the ratchet teeth, a lock pawl pivotally mounted on the casing for engagement with the ratchet teeth to prevent retrograde rotation of the tool member, and a spring interposed between the casing and the lock pawl urging said lock pawl into engagement with the ratchet teeth.

References Cited in the file of this patent UNITED STATES PATENTS 935,482 Fresko et al. Sept. 28, 1909 2,119,968 Shaft June 7, 1938 2,264,012 Wasson Nov. 25, 1941 2,491,624 Shaif Dec. 20, 1949