US3834828A

US3834828A - Electric drill holder

Info

Publication number: US3834828A
Application number: US00333349A
Authority: US
Inventors: Y Kikuchi
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-02-19
Filing date: 1973-02-16
Publication date: 1974-09-10
Anticipated expiration: 1991-09-10
Also published as: JPS4887490A

Abstract

Disclosed is an electric drill holder which provides a lever function in association with the electric drill, thus enabling one to apply a multiplied force to the drill bit in operation.

Description

United States Patent [191 Kikuchi [111 3,834,828 Sept. 10, 1974 1 ELECTRIC DRILL HOLDER [76] Inventor: Yukio Kikuchi, No. 15-10, S-chome,

Tateishi, Katsushika-ku, Tokyo, Japan Filed: Feb. 16, 1973 App]. No.: 333,349

[30] Foreign Application Priority Data Feb. 19, 1972 Japan 47-17584 US. Cl. 408/92, 408/712 Int. Cl B23!) 45/14 Field of Search 408/92, 712

References Cited UNITED STATES PATENTS 2,667,092 l/l954 Schaffer 408/92 5/1966 Meyer 10/1972 Salfer FOREIGN PATENTS OR APPLICATIONS 232,684 3/1910 Germany ..408/92 846,277 9/1939 France ..408/92 Primary Examiner--Andrew R. Juhasz Assistant ExaminerZ. R. Bilinsky [5 7] ABSTRACT Disclosed is an electric drill holder which provides a lever function in association with the electric drill, thus enabling one to apply a multiplied force to the drill bit in operation.

6 Claims, 4 Drawing Figures PATENTH] SEPI 01974 SHEET 1 OF 2 FAIENTED SEFI 01914 SHEET 2 0F 2 FIG.3

ELECTRIC DRILL HOLDER This invention relates to an electric drill holder, and more particularly to a holder device which provides a lever function in association with the electric drill, thus enabling a worker to apply a multiplied force to the drill bit in operation.

In operating an electric drill, a worker grips the handle of the device in his right hand, and positions the drill bit at a proper place, and at the same time he must apply the force to the device with his single hand to push the drill bit against the workpiece. In this connection the drill bit of a relatively large diameter cannot be used because of insufficient force to the drill bit. The drill bit as large as mm. in diameter is in fact, difficult to handle. This difficulty will be increased in drilling operation at an elevated place in a high-storied building as for instance in fixing a sign board to an elevated place. In these instances sometimes, a worker extends the full length of his arm to hold a relatively heavy device above his head, or sometimes he keeps his body twisted for the whole period of drilling operation. This will cause fatigue, and at the. same time it will put a worker into danger of falling. This danger will be enhanced by the sudden start of the counter rotation of the device body, which is caused by catching and preventing the drill bit from rotating just before the drill bit has passed through the workpiece. In the hope of overcoming the above difficulties, it has been hitherto proposed that an electric magnet be associated with an electric drill thus magnetically fixing the electric drill to the workpiece in operation. The combination of the electric magnet with the electric drill body makes the whole size of the device large and heavy, and therefore the device is difficult to handle. Also, such device is expensive.

An object of this invention is to provide an electric drill holder which is free from the defects above mentioned.

The advantages attributable to a unique design of the detachable type electric drill holder according to this invention are:

i. the force to push the drill bit against the workpiece can be multiplied by the lever action of the holder, and the force thus multiplied is sufficient to allow a rela tively large diameter drill bit to make a hole in the workpiece;

ii. the sudden counter rotation of the device body just before the completion of drilling operation is completely eliminated;

iii. the worker can operate the electric drill in an efficient way without being fatigued for a relatively long period of operation; and

iv. the worker can easily attach to and detach the holder from the electric drill. The holder itself, is light, stout, and inexpensive.

Other objects and advantages of this invention will be apparent fromthe following description when considered in connection with the attached drawings wherein:

FIG. 4 is similar to FIG. 2, showing another embodiment of this invention in section.

Referring to the drawings, a conventional electric drill having an electric motor incorporated therein, is indicated by reference numeral 1.. The electric drill has a grip 2 and a chuck 3. The chuck 3 is adapted to receive and clamp a drill bit 4. The neck portion of the drill body 1 is inserted in and fixed to a male annular member 7 by associated screws 8. As shown in FIG. 2, the male annular member 7 has a male-threaded projection 6. The male annular member 7 can threadly mate with a female annular member 5. The female annular member has female threads 5' on the inner sur face thereof and indentations 9 around the end thereof opposite to the threaded end. The spiral direction of threads 6 and 5' (for instance, in the left hand) are opposite to the rotating direction of the drill bit (for instance, in the right hand), thus causing the male annular member 7 to threadly mate with the female annular member 5 as the consequence of a counter reaction to the drill bit rotation. The female annular member 5 is adapted to receive a ring 10. The ring has indentations 11 formed along one circumferential edge thereof and a pair of axles l2 fixed on the peripheral surface thereof, as best shown in FIG. 3.

As mentioned earlier, the drill bit is often caught by the aperture edge just before the termination of drilling operation, and therefore the rotation of the drill bit is forcedly and suddenly stopped, thus causing the sudden counter rotation of the drill body with a relatively strong force. As best shown in FIG. 3, the indentations of the female annular member 5 and associated ring 10 are shaped in such a form that the strong force above mentioned will cause the annular member and associated ring to be put into locking condition, thus preventing the counter rotation of the drill body as described later in detail. Preferably, the indentations 9 and 1 1 is made inthe form of saw-tooth. However, they may be in the triangular form.

The axles 12 are positioned opposite to each other in a diametrical direction of the ring 10. The ring 10 is pivotally mounted in the collar portion 15 of the holder by inserting the axles 12 in associated holes 13. The collar portion 15 has a rod 24 connecting the opposite ends thereof.

As shown in FIG. 1, a hollow handle 17 of the holder suspends from the collar portion. As is best shown in FIG. 2, a lever 22 is pivotally connected to the upper portion of the handle 17 by a pivot pin 16. The lever 22 has an indented portion 21 in the vicinity of the pivot 16, and the handle 17 has a raised seat 17' projecting from the inner surface thereof.

An elongated flexible body such as a length of chain or steel wire 18 has a hook 19 attached to one end thereof. The other end of the chain or steel wire is connected to a spring coil 20 which is positioned at the bottom end of the handle, thus causing the chain or steel wire to be spring-biased at all times. As shown best in FIG. 2, the chain passes around the pivot pin 16, and then through the space between the indented portion 21 and the raised seat 17'. The chain 18' will be clamped between the indented portion 21 and the raisedseat 17 by pushing the lever 22 against the handle 17, thus preventing further pulling-in of the chain into the handle.

As is best shown in FIG. 2, the lever 22 has a hooking projection 25 on the lower portion thereof. Thehandle 17 has first and second holes in opposite facing relationship. The first hole '28 of the handle is made in the form of slit. A cylindrical latching member 26 is slidably mounted in the handle. The catch hole 27 of the latching member 26 is adapted to receive and catch the hooking projection 25 when the lever is pushed against the handle. The latching member 26 has a finger operated projection extending through the second hole of the handle. The latching member 26 is spring-biased in such a way that the hooking projection 25 and the catch hole 27 are put into the latching condition when the hooking projection 25 is inserted in the catch hole. Thus, the lever 22 when pushed against the handle will be kept closed, and at the same time the chain 18 will be clamped between the indented portion 21 and the seat'=l7. By pushing and moving the finger operated projection of the latching member against the resilient force of spring, the hooking portion 25 will be released from the catch hole 27. As a result the lever 22 is made free, and at the same time, the full length of the chain 18 will be automatically pulled into the hollow handle under the influence of the spring coil 20.

When the electric drill holder is in use, the neck of the drill body 1 is firmly fixed to the male annular member 7 by the associated screws 8. The worker holds the grip 2 of the drill body 1 in his right hand, putting the drill bit 4 on a desired position of an object, such as an L-shaped steel body a. Then, the chain 18 is drawn out from the interior of the handle 17. The hook 19 is then, caught by the object. The chain 18 will be tight under the influence of the spring coil 20. Then, the lever 22 is closed with the result that the chain 18 is clamped between the indented portion 21 and the raised seat 17', leaving a desired length of the chain out of the handle.

In the drilling operation the worker holds the electric drill 1 in his right hand and the holder in his left hand, and then he operates the switch lever 23. As the drill bit is advancing, the worker pulls and rotates counterclockwise the handle 17 about the pivot 16 as indicated by the arrow b in FIG. 1. Thus, the force to pull the handle is multiplied by power of a lever, and finally the force thus multiplied will be applied to the drill bit 4 via the axles 12 in the direction Otherwise, an elongated hook accessory 19 may be used in the manner as shown in the broken line in H0. 1. In this instance the handle 17 of the holder must be pushed and rotated clockwise about the rod 24 of the collar 15, which functions as the fulcrum of the lever system.

As is apparent from the above, in using the hooking chain 18, the length of handle 17 and the length portion of the collar extending from the pivot 16 to the hole 12 constitute together a lever system having the pivot 16 as the associated fulcrum. The worker can apply a strong force to the drill bit simply by rotating the handle counter-clockwise about the pivot pin 16 as indicated by the arrow b. In using'the hooking accessory 19', the total length of the handle plus collar, and the length portion of the collar extending from the rod 24 to the hole 12 constitute together a lever system having the rod 24 as the associated fulcrum. Likewise, the worker can apply a multiplied force to the drill bit by rotating clockwise the handle 17 about the rod 24. The worker can control the positioning of the drill bit by his right hand with ease because his right hand need not be used in applying the force to push the drill bit against the workpiece.

As mentioned earlier, the drill bit is often caught by the aperture edge just before the termination of the drilling operation, causing the sudden counter rotation of the drill body. This counter rotation will not affect the grip of the electric drill if it is used in association with the holder of this invention. Because the counterrotary force will be reduced to the minimum by the lever action before it exerts on the grip of the electric drill through the lever system, which consists of the radius length of the collar and the full length of the handle plus the radius length of the collar.

The

annular portions

7 and 5 are threaded in such a direction that the counter action to the drill bit rotation will make the threadly engagement tight in operation.

Referring now to FIG. 4, there is shown another embodiment of this invention. This embodiment is the same as that shown in FIGS. 1 to 3 except for the chain clamping mechanism. As shown in the drawing, the collar portion 15 has an extension 31 suspending from the lower side thereof. The upper end of the handle 17 is pivotally connected to the extension 31 by a pivot pin 32. The handle 17 has a detent 33 rising from the upper end thereof. The detent has an indented portion facing the extension 31. The handle 17 also has a hollow frustrum collar 34 slidably mounted to the shank of the handle. The chain 18 passes through the clearance space between the bottom of the collar portion 15 and the undersurface of the ring 10 and through the space between the extension 31 and the indented portion of the detent 33 and then the chain 18 comes into the hollow handle 17. With this arrangement, if the handle 17 is rotated counter-clockwise about the pivot pin 32, the chain 18 will be clamped between the extension 31 and the indented portion of the detent 33. Then, the slidable collar 34 is pushed into the remaining space between the extension 31 and the handle 17, thus wedging the handle 17 to the extension 31, and positively preventing the chain 18 from releasing from the detent 33.

I claim:

1. A holder for an electric drill having a neck portion coaxial with the axis of the drill comprising a hollow handle element having a collar portion, an annular assembly releasably mounted on the neck portion of the drill and provided with means for pivotally mounting said collar portion thereon, the axis of said handle element being at a substantial angle to the axis of said drill, a length of chain extending from the work to be drilled and then at a substantial angle to pass through said hollow handle element, means for releasably attaching the outer end of said chain to the work to be drilled, means for biasing said chain in said handle element and releasable means connected to said handle element for clamping said chain with respect thereto, whereby when said chain is clamped by said clamping means and when said handle element is pulled away from the work to be drilled the handle element will pivot about the point where the chain alters direction to pass through said handle element and thus exert pressure through said collar and said annular assembly to assist the drilling operation.

2. A holder as claimed in claim 1 wherein said annular assembly comprises a male annular member, means for securing said male member to the neck of the drill, a female annular member releasably secured to said male member and provided with indentations projecting axially thereof, a ring surrounding said female member and having indentations about one edge thereof for engagement with the indentations of said female member, said ring member being provided with said means for pivotally mounting said collar portion of said hollow handle element.

3. A holder as claimed in claim 2 wherein said indentations of said female member and said ring are shaped to interlock and thus prevent sudden counterclockwise rotation of said drill if the rotation of the drill bit suddenly stops while drilling.

4. A holder as claimed in claim 1 wherein said releasable chain clamping means comprises a lever pivotally mounted on said handle element, said chain passing over said pivotal connection for said lever and further includes an indented portion on said lever and a raised 6. A holder as claimed in claim 4 and further comprising latching means for holding said lever in clamping position against said chain.

Claims

4. A holder as claimed in claim 1 wherein said releasable chain clamping means comprises a lever pivotally mounted on said handle element, said chain passing over said pivotal connection for said lever and further includes an indented portion on said lever and a raised portion on the inside of said hollow handle element for engaging said chain when said lever is moved into clamping position.

5. A holder as claimed in claim 1 wherein said releasable chain clamping means comprises an extension extending from said collar, detent means attached to said handle element, means for pivotally mounting said handle member onto said extension, said chain extending over said last mentioned means, and a frustum collar slidably mounted on said handle element for locking the engagement of said detent means against the chain.

6. A holder as claimed in claim 4 and further comprising latching means for holding said lever in clamping position against said chain.