US3612554A

US3612554A - Screwdriver with substitutable bit

Info

Publication number: US3612554A
Application number: US737871A
Authority: US
Inventors: Katsuyuki Totsu
Original assignee: Individual
Current assignee: Individual
Priority date: 1967-06-24
Filing date: 1968-06-18
Publication date: 1971-10-12
Anticipated expiration: 1988-10-12
Also published as: FR1571177A; CH490167A; GB1234798A; DE1703630B1

Abstract

This screwdriver comprises a sleeve shank which at its end portion is provided with a slot and a center cavity bisecting said slot into which a bit is substitutionally inserted. The sleeve shank end is covered with a sleeve adapter of plastic material which serves to hold and suspend the screw.

Description

United States Patent Inventor Kats'uyuki Totsu No. 4-7, S-ehome, oshiage, Sumida-ku, Tokyo, Japan Appl. No. 737,871 Filed June 18, 1968 Patented Oct. 12, 1971 Priority June 24, 1967, Mar. 6, 1968 Japan 42/40239 and 43/ 14040 SCREWDRIVER WITH SUBSTITUTABLE BIT 9 Claims, 22 Drawing Figs.

U.S. Cl 279/102 Int. Cl B25g 3/10, B25b 15/00 Field of Search 145/50; 30/340, 329, 336, 342; 287/126; 279/102, 93, 104, 96

References Cited UNITED STATES PATENTS 10/1966 Scott et a1. 30/342 5/1899 Sawyer 145/50-1 1/1907 North 145/50-1 8/1919 Mowers 145/50-1 UX 6/1933 Beaver 279/93 2/1942 Snyder 279/93 X FOREIGN PATENTS 1/1914 Great Britain 145/50-1 Primary Examiner-Robert C. Riordon Assistant Examiner-Roscoe V. Parker, Jr. Attarney-Jecies and Grenside ABSTRACT: This screwdriver comprises a sleeve shank which at its end portion is provided with a slot and a center cavity bisecting said slot into which a bit is substitutionally inserted. The sleeve shank end is covered with a sleeve adapter of plastic material which serves to hold and suspend the screw.

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FIGZZ INVENT OR SCREWDRIVER WITII SUBSTITUTABLE BIT BACKGROUND OF THE INVENTION FIGS. ll(a) (b) to 14(a) (b) show front elevations and lateral views in section of the alternative embodiments of the 7 bits;

This invention relates to improvements in the screwdriver,

and more particularly to the screwdriver of the type employing a substitutable bit.

In the screwdriver heretofore used, the tendency of abrasion and detriment usually occur at the bit portion of the screwdriver due to continuous driving and disengaging operations and as a result the screwdriver in its entirety is not serviceable for further use since the bit is integrally constructed with the shank of the screwdriver. In that case the screwdriver should be discarded, otherwise the bit will be ground or polished for restoration under the special care.

SUMMARY OF THE INVENTION Generally, therefore, it is an object of the present invention to obviate the above and other disadvantages and difficulties and to provide a novel screwdriver which has certain structural and functional features of advantages over the similar screwdriver of the prior art and is economic in manufacture and simple in construction.

A principal object of the invention is to provide a screwdriver having a sleeve shank provided at its extremity with a slot and a center cavity bisecting the said slot serving to receive the bit.

Another object of the invention is to provide a bit which comprises a blade portion and a tail piece and is substitutionally inserted in the slot and the center cavity provided at the end of the sleeve shank of the screwdriver.

A further object of the invention is to provide a bit having a pin adapted to be rigidly engaged with a screw slot provided in the screw head thereby holding the screw to carry the same to the position where the driving operation is effected.

Still another object of the invention is to provide a new screwdriver in which a sleeve shank end containing the bit is covered with a sleeve of plastic material which at its open end envelopes the screw head thereby holding the screw to carry the same to the position where the driving operation is effected.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

In brief the screwdriver embodying the invention comprises the sleeve shank provided at its extremity with the slot and the openended cavity bisecting the said slot into which the substitutable bit is rigidly inserted. The open-ended cavity is positioned in the center of the bottom plane of the sleeve shank and of the greater depth than that of the slot. The sleeve shank at its extremity is further provided with means for holding and suspending the screw internally or externally.

BRIEF DESCRIPTION OF THE DRAWING For a fuller understanding of the nature and object of the invention a reference should be had to the following detailed description taken in connection with the accompanying drawing, in which the same reference numerals designate the same or similar parts throughout the drawings;

FIG. I is a fragmentarily enlarged lateral view of the end of the sleeve shank free of the bit;

FIG. 2 is a bottom view of FIG. 1;

FIG. 3 is a longitudinally sectioned lateral view of FIG. 1;

FIG. 4 is a front elevation of the bit according to the invention;

FIG. 5 is a lateral view of FIG. 4; I

FIG. 6 is a fragrnentarily enlarged front view of the end of the sleeve shank associated vention;

FIG. 7 is a sectional view of FIG. 6;

FIG. 8 is a longitudinally sectioned lateral view of FIG. 6;

FIG. 9 is a front elevation of the bit embodying the inven-' tion where a protuberance is provided at the middle of the lower edge;

FIG. 10 is a perspective view of the screw having the screw slot with the center cavity bisecting the same;

with the bit according to the in- FIG. 15 is a longitudinally sectioned view of the sleeve shank end having a slot provided with a bypath and a vertical channel; 7

FIG. 16 is a bottom view of FIG. I5;

FIGS. 17(a) (b) and 18(a) (b) are back and lateral views of the bit similar to FIGS. 9 and 14 but provided with pins adapted to engage with the screw slot thereby holding the screw;

FIG. 19 depicts the state that the bit with the pin as illustrated in FIG. 18 is inserted in the slot with bypath and vertical channel provided in the sleeve shank end;

FIG. 20 is longitudinally sectioned view showing the state that the bit with the pin fitted to the shank as illustrated in FIG. 19 is inserted in the screw slot of the screw head thereby holding the screw;

FIG. 21 is a longitudinally sectioned lateral view in fragmental of the shank end with the bit as illustrated in FIGS. 4 and 5 holding the screw through an outer sleeve adapter;

FIG. 22 is a longitudinally sectioned lateral view in fragmental similar to FIG. 20 showing that the outer periphery of the sleeve shank end is threaded.

DESCRIPTION OF THE PREFERRED EMBODIMENTS As illustrated by way of example in the drawings, the characteristic feature of the invention comprises a sleeve shank which at its one end is provided with a slot and the center cavity bisecting the said slot which is positioned in the center of the shank end and about the longitudinal axis of the sleeve shank, and a bit which is substitutionally and rigidly inserted in the slot and the center cavity.

In FIGS. [to 3, the shank end I is provided with a slot 2 and the center cavity 3 which bisects the said slot 2 and is positioned in the center of the shank end and about the longitudinal axis thereof. Alternatively, the shank end may be provided with the slot with a bypath and/or a vertical channel serving to receive a specially designed bit as hereafter described.

It will be noted that the center cavity 3 has a greater diameter than the width of the slot 2 and a greater depth than that of the said slot 2.

In FIGS. 4 to 8, the bit 4 according to the invention comprises a blade 5 and tailpiece 6 and is formed preferably of elastic steel although the nature of the material for forming the bit may optionally be selected as desired according to the purpose. The bit 4 is of substantially the same dimensions as the slot 2 in its horizontal length but greater than the slot 2 in its vertical length, so that the blade when the bit is inserted in the slot 2 protrudes over the slot 2 for engagement with the screw slot of the screw head. Moreover, it will be noted that the thickness of the bit 4 is substantially the same as width of the slot 2, so that the bit 4 is tightly engaged with the slot 2. The tailpiece 6 is somewhat bent to one side at its root 7 as shown in FIG. 5, so that the tip of the tail 6 when forced into the center cavity 3 engages rigidly with the inner wall thereof due to the elasticity of the bent tailpiece as will be apparent from FIG. 8. For this reason, the center cavity 3 may be of any desired shape although the cylindrical shape is rather convenient in the mechanical working.

On the insertion of the bit 4 in the slot 2, the tailpiece 6 is first guided into the center cavity 3 and then the edge of the blade portion 5 is tapped with a certain tool until the upper end of the blade portion faces with the bottom surface of the slot 2. Further, since the tailpiece 6 is somewhat bent as shown in FIG. 5, the top end thereof is pressed to the inner wall of the center cavity and does not disengage spontaneously during the screwing or unscrewing operations unless the bit is forcefully withdrawn.

The bit when it is to be replaced by a fresh one may readily be withdrawn with a tool such as pincers.

In FIG. 9, the blade edge 5 at its middle is provided with a small projection 8, which is particularly applicable to the screw of the type employing the slot possessing a center cavity of a greater depth than that of the screw slot as shown in FIG. 10. It will be appreciated that the projection 8 when inserted in the cavity 9 provided in the screw head 10 serves as the further means to prevent the driver blade from slipping sideways out of the screw slot 11.

FIGS. 11(0) (11) to 14(a) (b) show other embodiments of the bits having no tailpiece in which a bit 12 shown in FIG. 11 comprises a steel piece of substantially rectangular shape and its center portion is opened to form a protuberance 13 having the same ability as the tailpiece 6. According to this embodiment, the

opposite edges

14 and 15 are of the same thickness so that if one edge is worn-out or damaged then the other edge may be used for the further driving purposes.

In FIG. 12, the edge 15 is of less thickness than that of the edge 14 so that the bit may be applicable to screw slots of different widths.

In FIG. 13, a curved pin 16 in its one end is welded to the end of the bit 4. According to this embodiment, only the edge 14 is serviceable as a blade to be engaged with the screw slot. The pin 16 may be formed of anelastic steel while a blade may be selectively formed of a hard metal as desired according to the purpose.

In FIG. 14, a part of the bit 12 below the protuberance 13 is cut away, so that the edge 14 is divided into two symmetrical blade pieces 17. This type of the bit is rather convenient in the manufacture. It will be appreciated that such the divided blades 17 have the same effect as the straight and continuous edge 14 since the driving force generally exerts on the opposite outer ends of the edge.

On application of the bits as shown in FIGS. 11 to 14 which have no tailpiece, the slot 2 may be provided with a bypath 18 serving to receive the protuberance 13 or the curved pin 16 of the bit 12 as shown in FIGS. 15 and 16 thereby ensuring smooth insertion of the bit into the slot and precluding an undesireable displacement of the bit during the driving or disengaging operation.

In FIGS. 17 and 18, the bits at their respective rear sides are provided with 18, the 20 and 21 of elastic material serving to hold the screw. It will be noted that one end of the pin is welded to the end of the tail or bit while the other end of the pin being opened outwardly. When the bit associated with the pin is inserted in the slot, the pin is pressed toward the bit resisting to its outward elasticity as shown in FIG. 19. In this state, the pin pressed toward the bit keeps stronger elastic potency than the original state, i.e. before the pin being inserted in the slot of the driver shank. As is shown in the drawing, the bit and the pin are kept in very close but forming a clearance therebetween and ready for insertion in the screw slot. Accordingly, when the bit is inserted in the screw slot, the pin is further pressed by the inner wall of the screw'slot or by the center cavity provided in the screw head and as a result the screw 22 is rigidly held as shown in FIG. 20. In case of the bit of the type as illustrated in FIG. 18 which has no tailpiece the shank end I may be modified to the type as illustrated in FIG. 16 wherein a vertical channel 19 serving to receive the pin 20 is provided on the opposite side to the bypath 18.

In FIGS. 21 and 22, the outer periphery of the shank end 1 is covered with a sleeve adapter 23. This sleeve adapter 23 is formed of soft plastic material for example such as vinyl chloride and when it is applied around the shank end, the diameter at the lower opening of the sleeve adapter tends to become smaller than that of the shank end, so that the outer periphery of the screw head is held by the inner wall of the sleeve end 24 as shown in FIG. 21. On the other hand, the upper end of the sleeve adapter 23 falls in the recess 25 provided around the upper portion of the shank end 1, so that a step 26 of the recess 25 precludes the sleeve adapter 23 from sliding upwardly along the outer periphery of the sleeve shank.

It will thus be seen that the screwdriver in accordance with the invention provides a substitutable bit and a prositi e holding ofthe screw therebyf acilitatihg m's'crwm'g or unscTEwing operation conveniently. Further according to the invention, the bit has an uniform thickness through all its area and is not tapered as can be seen in the ordinary blade of the screwdriver. Accordingly, when the bit is engaged with the screw slot, both sides of the bit are tightly faced with the inner sidewalls of the screw slot and therefore the driving operation may be carried out more effectively with less fear that the bit will jump out of the screw slot.

Moreover, since the structure is relatively simple, the screwdriver in accordance with the invention may be manufactured at a low cost and also the bit only may be manufactured with negligible cost. Further, it will be appreciated that it is an important merit of the invention that the bit only which is considered as the most vital part of the driver may be formed of a hard steel of selected quality while the shank may be formed of ordinary metal at reduced cost.

While certain preferred embodiments of the invention have been illustrated by way of example in the drawings and particularly described, it will be understood that modifications may be made in the constructions and that the invention is no way limited to the embodiments shown. For example, while the invention has been described as relating the screws of rounded heads, it would not differ from the present invention to make use of it in connection with flat screw.

What is claimed is:

1. In combination, a screwdriver shank having an axially extending cavity and a diametrically extending slot in the operative end of said shank, said cavity communicating at the lower end thereof with said slot, and a bit comprising a blade member and a cooperating resilient member angularly oriented with respect to the blade member, said bit being detachably positioned within the cavity with its blade member tightly engaged within said slot and with a part only of said resilient member in rigid engagement with a portion only of the interior wall defining the cavity and forming thereby the sole retaining means for retaining said bit within said cavity, one end of said blade member protruding beyond said slot for engagement with a screwhead.

2. The combination according to claim 1, wherein said resilient member is resiliently urged substantially in the plane of the remaining portion of said blade member by contact with the wall of said cavity upon insertion of said blade member in the slot of said shank, said bit between the regions of contact with the wall of the cavity and said slot being spaced from the cavity wall.

3. The combination of claim 1, wherein the end of said blade member protruding beyond said slot is provided with a projection adapted to seat in a slot ofa screwhead.

4. The combination according to claim 2, wherein said resilient member is provided with resilient pin angularly oriented with respect to the member.

5. The combination of claim 1, wherein the diameter and depth of said cavity are greater than the thickness and depth respectively of said slot.

6. The combination according to claim 5; wherein the apertured end of said shank is provided with a sleeve adapter the upper end of which contacts a shoulder formed on the outer periphery of said shank and the lower end of which is adapted to embrace a screwhead.

7. The combination according to claim I, wherein said resilient member is an angular tang welded to the end of the blade member remote from said one end.

8. The combination according to claim 1, wherein said one end of the blade member is provided with a pair of bifurcations serving as blade pieces, said resilient member comprising a tang separating said bifurcations, said tang projecting from one face of the blade member, a resilient pin being provided on the other face of said member and being angularly oriented with respect thereto, said pin being substantially the same length as the blade member.

9. The combination according to claim 8, wherein said cavity includes an axially extending bypath groove formed in one wall defining said slotizmtl includes a channel formed in the other wall defining said slot, said channel being adapted to receive said pin and said groove being adapted to receive said tang.

Claims

3. The combination of claim 1, wherein the end of said blade member protruding beyond said slot is provided with a projection adapted to seat in a slot of a screwhead.

7. The combination according to claim 1, wherein said resilient member is an angular tang welded to the end of the blade member remote from said one end.

9. The combination according to claim 8, wherein said cavity includes an axially extending bypath groove formed in one wall defining said slot and includes a channel formed in the other wall defining said slot, said channel being adapted to receive said pin and said groove being adapted to receive said tang.