US2815837A - Ratchet screw driver - Google Patents

Description

United States Patent RATCHET SCREW DRIVER Porter S. Morgan, Westport, Conn., assignorrto Morgan Development Laboratories, Inc., Westport, Conn, a corporation of Delaware Application April 20, 1955, SerialNo. 502,618

Claims. (31. 192-44 This invention relates to a ratchet screw driver and more specifically to a novel reversibleclutch means for use therewith.

An object of this invention is to provide a novel reversible clutch means for a screw driver whereby the clutch means is engaged merely by an axial pressure applied to the handle of the screw driver, and the direction in which the clutch drives the bit is controlled simply by the direction in which the handle is rotated.

It is another object of the present invention to provide means whereby upon the return axial movement of the handle when manual axial pressure upon the handle is released, the clutch is automatically and instantly, without further effort on the part of the operator, disengaged sothat the handle is rendered freely rotatable relative to the bit.

These objects are accomplished by a screw driver having a handle coupled to the work-engaging portion thereof so as to be axially and rotatably moved relative thereto. A novel clutch means having cooperating spaced surfaces and rollers disposed therebetween is positioned within the handle of the tool. One of the cooperating surfaces of relative to the shank.

the clutch means includes a sleeve having an internal conical wall which is fixed to the handle and movable therewith. Cooperating with the sleeve and coaxially spaced therefrom is a frustro-pyramidal' member which is connected to the shank of the bit so that the outer faces of the pyramid are substantially parallel with and spaced from the interior conical surface of the sleeve. Between these two surfacesthere are provided a plurality of rollers one for each face of the pyramid, and which are normally maintained out of driving relation with said surfaces. When the'handle is moved axially by a force applied thereto, the cooperating tapering surfaces are brought together so that upon rotation of the handle, the rollers are wedged therebetween to lock the handle to the shank so that the latter may be driven by continued rotation of the handle. Means are further provided so that upon releaseof axial pressure on the handle, the handle moves outwardly and the rollers are automatically and instantly moved into non-wedging position'so that the handle becomes freely rotatable in either direction relative to said shank.

Other features and advantages will be. apparent from the specification and claims when considered with the drawings in which:

Figure 1 is an elevational side view of the ratchet screw driver having a portion'therefor broken away to better illustrate the clutch means of the present invention.

Fig; 2 is an enlarged sectional view of the screw driver handle of the present invention showing the clutch in greater detail.

Fig. .3 is a sectional plan view taken along line 3-'3 of Fig. 2.

Fig. 4 is a sectional plan view taken along. line 4-4 of Fig'. 2.

The present invention is directed to a reversibleratchet.

2. screw driver10 having a handlell, afwor'k-engaging portion 12 and a novel clutch means 13 to connect the work-engaging portion in driving relationship with the handle.

In the illustrated embodiment, the screw driver 10 in which the clutchof the present invention has particular utility, includes a work-engaging portion 12 having. a shank 14 provided with a bit 15 on the lower'end thereof. The upper end 16' of the shank extends into the interior of a hollow handle 11.

According to this invention the handle 11 is axiaHy and rotatably coupled to the shank 14 and is made in two parts 17 and 18. The lower part 17 is provided with inturned flange portions 19 which circu'mscribes anope'ning 20 for receiving the upper end 16 of the shank 14. The upper part 18 of the handle consists of a cupshaped member which is connected to the lower part 17 by'any suitable means to form therewith a housing for enclosing the novel clutch means 13. In order to facilitate assembly and disassembly of the handle, the two handle parts are provided with cooperating threaded portions 17a and 18a tosecure them together. It will be under stood that the handles are suitably shaped to facilitate handling, and as shown, the top 18b is rounded to fit the palm of the hand while the side walls are fluted for gripping.

As' it will be more fully set' forth the handle of the ratchet screw driver is axially and rotatably coupled to the shank'so that normally, i. e. when the tool is not in use, the handle is maintained inthe unclutched position In order that the handle may be connected in driving relationship with the shankso that the latter can be driven in a direction in which the handle is rotated, the novel clutch means is positioned between the upper end of the shank and the handle.

The clutch means 13 is arranged within the handle 11 so that when an axial force is applied to the handle in the direction in which the tool bit 15 engages a work piece, e. g. a screw (not shown), the clutch becomes engaged, whereupon initial rotation of the handle in'eithe'r" direction causes the work-engaging portion of the tool to be locked with the handle and to be'driven accordingly. An important feature of this invention, as it will be fur-' ther pointed out, is that the shank is maintained in clutched or driving relationship relative to the handle only as long and so long as an axial force is applied and main tained on the handle. pressure, the clutch means is automatically disengaged so thatthe handle may be ratcheted in the opposite direction without disturbing the work-engaging portion.

This is accomplished, according to the present invention, by a clutch means consisting of a pair of spaced,'

sleeve is conically formed. The sleeve member 21 is fixed to the interior portion of the handle by any suit-" able means so that it will always rotate with the handle,

the interior wall 21a of the sleeve being smooth to form' one of the cooperating camrning surfaces. The other co-- operating camming surface is in the form of a polyhedralshaped member 22, preferably a frusto-pyramidal member 22 which is fixed to the shaft.

While the member 22 may be keyed to the shaft by.

any suitable means, as shown in Figs. 2 to 4, the upper portion of the shaft is provided with a shoulder23 havingv a squared portion 24 extending upwardly therefrom and the member 22 provided with a square bore 25- receives Patented Dec. 10, 1957 Thus, upon release of the axial the squared portion 24 of the shaft so that member 22 is fixed thereto to be moved therewith. Thus the members 21 and 22 are relatively movable to each other.

In the illustrated form the frusto-pyramidal member 22 has a plurality of sloping faces 22a which are inclined substantially at the same angle as that of the inner surface 21a of the sleeve member 21. As shown in Fig. 3 the member is provided with eight faces, each face being spaced from the inner wall of the sleeve.

Disposed between the cooperating camming surfaces 21a and 22a, there are provided a plurality of rollers 26, one for each face of the pyramid, the rollers 26 being normally positioned approximately in the vicinity of the midpoint of each face as shown in Fig. 3. In order that the rollers 26 may be equally spaced, they are positioned in a cage 27, the latter being provided with slotted openings 27a, each accommodating a roller 26. As shown in Fig. l the cage is inclined at substantially the sanle'angle as are the faces 22a of the pyramid and is provided with an inturned flange 27b by which it is supported on the pyramid member. It will be noted that the cage 27 and rollers 26 supported thereon are movable relative to the surfaces 21a and 22a since the cage is independently supported therebetween. It will be further noted in Figs. 2 and 3 that the diameter of the rollers 26 is slightly smaller than the spacing between the midpoint of the faces 22a and in the wall 21a of a sleeve member when the tool is in normal position, i. e., when the tool is not in use. Therefore, the handle is normally freely rotatable about the workengaging portion.

-To engage the handle 11 into clutching relationship with the shank 14 so that the latter may rotate in the direction in which the handle is rotated, the handle is mounted on the shank so that the lost motion required to close the space between the rollers and the sleeve is taken up by axial movement of the handle. Thus, when an axial force is applied to the handle, the latter is displaced axially as shown by the dotted lines of Fig. 2. As a result the conical sleeve 21 fixed to the handle is urged toward the pyramid member 22 so that it is brought to bear upon the rollers 26. Consequently the surfaces-21a and 22 are closed upon the rollers, so that upon rotation of the handle the rollers are circumferentially moved or eammed into wedging position between an outer edge 22!; of the faces 22a and the inner wall surface 21a of the sleeve, thus locking the shank 14 of the tool in driving relationship with the handle, regardless of the direction in which the handle is rotated. Since the lost motion between the parts is very slight, the amount the handle is moved before the clutch is engaged is very slight and practically imperceptible.

To automatically return the handle to its outward or normal position upon release of the force applied axially to the handle, a resilient means is positioned between the end of the shank and the top of the handle so that the latter is normally urged outwardly. As shown in Figs. 1 and 2, the resilient means is in the form of a compression spring 28 which is held in place by a recess 29 formed on the inner side of the handle. A depending wall 30 surrounding the recess forms a housing for the spring 28 and functions also as a guide for the handle as it is axially displaced for clutching engagement. To provide clearance during axial displacement of the handle, the pyramid member 22 is formed with a recess 31 to receive the depending wall portion 30. Slidably mounted within the housing there is provided a bearing cup 32, and it will be noted that the bearing cup 32 is urged into engagement with the top of the shank. In this manner the spring 28 is maintained in axial alignment between the handle and the shank. To limit the outward movement of the handle, the shank 14 is provided with a collar or stop ring 33 adjacent the lower interior portion of the handle so that in normal position the inturned flange 19 is in abutting relationship therewith.

. Accordingly, when it is desired to engage the handle in driving relationship with the shank, axial pressure applied to the handle in the direction in which the bit engages a screw compresses the spring, and the handle is axially displaced as shown in Fig. 2. As the sleeve 21 is axially displaced, it closes the space between the rollers and the sleeve so that the rollers are engaged by the camming surfaces 21a and 22a. Upon the initial rotation of the handle, the rollers are moved in the direction in which the handle is rotated, so that they become wedged between outer face 22a and edge portion 22b of the surface 21a of the sleeve. With the rollers so wedged or locked the shank is put in driving relationship with the handle. This wedging or driving relationship is maintained as long as an axial force is maintained on the handle. Upon release of the axial force, the handle is urged outwardly by the spring 28 to its normal position as shown by the solid lines in Fig. 2. Thus the shank becomes unclutched from the handle and is rendered freely rotatable about the handle, allowing the handle to be ratcheted without disturbing the shank portion of the tool.

In order that the rollers 26 may be returned automatically and instantly to their neutral position upon the disengagement of the clutch, as shown in Fig. 3, Without any further effort on the part of the operator, the following novel arrangement is provided. As best seen in Fig. 2, the lower portion of the pyramid member is provided with a shoulder 22c and cutdown portion 22:! to accommodate a collar 34 having oppositely spaced, upwardly projecting lug members 35 and 36. The cage 27 likewise is provided with a pair of oppositely positioned depending tongues 37 and 38 which are spaced from and aligned with the projecting lugs 35 and 36 respectively. See Figs. 2 and 4.

Between the shoulder 22c and the collar 34 there is disposed about the cut-down portion 22d a pair of spring members 39 and 40 which are arranged thereon and cooperate with the lugs 35-36 and tongues 37-38 to automatically return the cage and rollers to neutral position as shown in Fig. 3. To accomplish this, the springs 39 and 40, as illustrated, are formed in a pigtail loop which are circumscribed about the cut-down portion 22d,

2 preferably in superimposed relationship.

The spring 39 is disposed about the cut-down portion 22d so that the outer erids thereof 39a and 39b normally maintained so as to be in engagement with the outer edge 35a and 36a of the lugs 35 and 36, and with the outeredge 37a and 38a of tongues 37 and 38. The other spring 40 is arranged so that its ends 40a and 4012 are normally in engagement with the opposite edges 35b and 36b of the lugs 35 and 36 and 37b and 38b of the tongues 37 and 38. See Fig. 4.

Because the collar and the projecting lug portions are fixed to the shank, it will be noted that if the handle is rotated so as to engage the clutch, the cage is caused to be rotated slightly in the direction in which the handle is rotated before the rollers become wedged. Consequently, if the handle is rotated counterclockwise until the clutch is engaged in driving relationship, the tongues 37 and 38 are moved against the bias of spring ends 39a and 40b respectively, the other ends 3912 and 40a of the springs 39 and 40 being held against movement by the stationary lugs 35 and 36. Thus it will be seen that as long as the clutch is engaged, the tongues 37 and 38 are maintained against the force of the spring 39 and 40 so that upon release of the axial pressure upon the handle of the screw driver, the spring 28 acting substantially simultaneously returns the handle to normal position while springs 39 and 4t reset the cage and rollers carried thereby to the position shown in Figs. 2, 3 and 4.

If the handle is rotated clockwise, the operation of the springs 39 and 40 on lugs 35 and 36 and tongues 37 and 38 is reversed. That is, the tongues 37 and 38 are urged clockwise and against the force exerted by spring ends 40a and 3%. Thus upon release of the clutch, the springs 39 and 40 cause the cage to be reset in the manner above described and as a result the cage is automatically reset as shown in Figs. 3 and 4, regardless of the position in which the handle is rotated. Because of the automatic resetting feature above described, the lost motion in clutching the tool is equalized in either direction and also the lost motion is reduced to a minimum.

As shown and described, the novel screw driver of the present invention is simple in construction, convenient to handle and positive in operation. An important feature of the present invention resides in the provision that the clutch is engaged simply by an axial force applied to the handle, whereupon the initial rotation thereof in either direction engages the shank into driving relationship with the handle. Further, the device of the present invention is provided with a clutch means that is automatically reset upon release of the axial force applied on the handle. As a result, the lost motion between the shank and the handle is reduced to a minimum, and what lost motion there is, is equalized in both directions of rotation.

Variations and modifications may be made within the scope of the claims and portions of the improvements may be used without others.

I claim:

1. A reversible ratchet screw driver having a shank, a handle coupled to said shank so as to be axially and rotatably moved relative thereto, a clutch means disposed between the handle and the shank for connecting and disconnecting the handle in driving relationship to said shank, said clutch means including spaced, sloping, cooperating surfaces adapted to be axially and rotatably moved relative to each other, rollers disposed parallel with and between said surfaces, said rollers being cammed between and into gripping and driving relation with said surfaces when axial pressure is applied to the handle so that upon initial rotation of the handle the rollers are in driving relationship with the handle and the shank in all rotative positions thereof so that said shank rotates therewith, and resilient means for automatically releasing said clutch means and returning said rollers to nondriving position upon the release of said axial pressure whereby the handle becomes freely rotatable relative to said shank.

2. A reversible ratchet screw driver having a shank, a handle coupled to said shank so as to be axially and rotatably moved relative thereto, a clutch means disposed between the handle and the shank for connecting and disconnecting the handle in driving relationship to said shank, said clutch means including a sleeve having a smooth, inner, conical surface, said sleeve being mounted in said handle to move therewith, a pyramid fixed to said shaft, said pyramid being coaxially spaced from and within said sleeve, rollers disposed between said sleeve and pyramid so that axial pressure applied to the handle causes said roller to cam therebetween and into gripping and driving relation therewith so that initial rotation of the handle circumferentially displaces the rollers to lock said handle and shank in driving relationship in all rotative positions thereof so that said shank rotates therewith, and resilient means for automatically releasing said clutch means and returning said rollers to nondriving position upon the release of said axial pressure whereby the handle is freely rotatable relative to said shank.

3. A reversible ratchet screw driver having a shank,

a handle coupled to said shank so as to be axially and rotatably moved relative thereto, a clutch means disposed between the handle and the shank for connecting and disconnecting the handle in driving relationship to said shank, said clutch means including a truncated, conical sleeve mounted in said handle to move therewith, a truncated pyramide fixed to said shaft, said pyramid being coaxially spaced from and within said sleeve, a cage disposed between and at all times out of contact with said sleeve and pyramid, rollers supported by said cage, said rollers being disposed between said sleeve and pyramid so that axial pressure applied to the handle causes said rollers to be cammed therebetween into gripping and driving relation therewith so that upon initial rotation of the handle the latter circumferentially displaces the rollers so as to lock said handle and shank in driving relationship in all rotative positions thereof so that said shank rotates therewith, and resilient means for automatically releasing said clutch means and returning said cage and rollers to normal inoperative position upon the release of said axial pressure whereby the handle is freely rotatable relative to said shank.

4. A reversible ratchet screw driver having a shank, a handle coupled to said shank so as to be axially and rotatably moved relative thereto, a clutch means disposed between the handle and the shank for connecting and disconnecting the handle in driving relationship to said shank, said clutch means including a truncated, conical sleeve mounted in said handle to move therewith, a truncated pyramid fixed to said shaft, said pyramid being coaxially spaced from and within said sleeve, a cage, rollers supported by said cage, said cage and rollers being disposed between said sleeve and pyramid so that said rollers are normally spaced from said sleeve thereby allowing said handle to be freely rotatable relative to said shank until the handle is displaced axially by a force applied thereto, to cause said rollers to be cammed between said sleeve and pyramid and into gripping and driving relation therewith and upon initial rotation of the sleeve, said rollers are circumferentially displaced to lock said handle and shank in driving relationship in all rotative positions thereof so that said shank rotates therewith, and means for automatically releasing said clutch means upon the release of said axial pressure, said means including a spring axially disposed between said handle and shank, normally urging the two apart upon release of axial pressure whereby said rollers are moved into non-wedging position and the handle is automatically rendered freely rotatable relative to said shank.

5. A reversible ratchet screw driver having a shank, a handle coupled to said shank so as to be axially and rotatably moved relative thereto, a clutch means disposed between the handle and the shank for connecting and disconnecting the handle in driving relationship to said shank, said clutch means including a truncated, conical sleeve mounted in said handle to move therewith, a truncated pyramid fixed to said shank, said pyramid being coaxially spaced from and within said sleeve, a cage, rollers loosely supported by said cage, said cage and rollers being disposed between said sleeve and pyramid so that said rollers are normally spaced from said sleeve thereby allowing said handle to be freely rotatable relative to said shank until the handle is displaced axially by a force applied thereto to cause said rollers to be cammed therebetween and upon initial rotation thereof to wedge said rollers therebetween to lock said handle and shank in driving relationship in all rotative positions thereof so that said shank rotates therewith, and means for automatically releasing said clutch means upon the release of said axial pressure, said means including a spring disposed between said handle and shank, normally urging the two apart, and spring means mounted on said shaft engaging said cage so that upon release of axial pressure, said cage and rollers are automatically reset to their normal non-wedging position whereby said handle is rendered freely rotatable relative to said shank.

Harrold May 7, 1929 Kesterton Feb. 14, 1950

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