CA2704814A1 - Electric drive unit for a "multi-bit dual-mode screwdriver for either manuel or powered actuation" - Google Patents

Abstract

An electric drive unit for a "Scruzol" (a "Multi-Bit Dual-Mode Screwdriver For Either Manual Or Powered Actuation"). Said drive unit is comprised of a substantially cylindrical, handheld housing, said housing having a hexagonal scabbard axially formed into one end for storage of a Scruzol's shaft. A hexagonal drive stub protrudes axially from said housing's opposite end and is configure for mating into a Scruzol's handle-end bit-socket for powered rotation of its shaft-end bit-socket. Said drive stub is powered by an internal electric motor, an internal battery and external motor control switches. A circular shroud protrudes from said housing to surround said drive stub such that the drive unit may be stored vertically onto a flat horizontal surface. The concave area surrounding said drive stub includes electrical contacts for mating onto an external battery charger.
Said battery charger may include side-prongs that plug directly onto a standard electrical wall outlet, thereby providing both electrical power and wall support for both charger and drive unit being charged. Said charger has an upper surface formed such that the vertically oriented drive unit mates directly onto electrical contacts for charging. A belt clip may be provided to facilitate carrying both the drive unit and its stored Scruzol. Lighting means may also be provided proximate to said drive stub for illumination of said Scruzol while in its powered mode of activation or else for general purpose use as a flashlight while said Scruzol is stored in its scabbard.

Description

ELECTRIC DRIVE UNIT FOR A "MULTI-BIT DUAL-MODE SCREWDRIVER
FOR EITHER MANUAL OR POWERED ACTUATION"

Field of the Invention The present invention is an electric drive unit for rotating a screwdriver.
More specifically: this invention optimally actuates a "Multi-Bit Dual-Mode Screwdriver For Either Manual Or Powered Actuation" such that it can be more effectively used in both its manual and its powered modes of operation.

Background of the Invention The present invention is conceived to exploit the physical and magnetic characteristics of my previous invention entitled "Multi-Bit Dual-Mode Screwdriver For Either Manual Or Powered Actuation" (Canadian patent # 2,541,354). This dual-mode screwdriver has been commercialized under the trade name "Scruzol", which for the sake of brevity and clarity is hereinafter referred to as a "Scruzol" when describing the present invention.

A Scruzol utilizes a reversible shape that enables its actuating force to be applied either manually or by being gripped in the chuck of a conventional electric drill. A Scruzol resembles a typical multi-bit screwdriver in that it has a magnetic bit-socket located in the end of a screwdriver shaft and a handle formed over the opposite end of said shaft, thereby enabling the user to apply manual torque to a screwdriver bit that's been inserted into its bit-socket. What's unique and particularly useful about the Scruzol is that it has an auxiliary magnetic bit-socket formed into the rounded end of its handle and this enables its shaft to be gripped in the chuck of a conventional electric drill to power-drive a bit that's been inserted into said auxiliary bit-socket.

In its preferred embodiment, a Scruzol also stores a plurality of spare screwdriver bits in its handle using a large central magnet to retain the bits within longitudinal, open-sided storage slots. This powerful bit-storage magnet also provides several useful side benefits:

1) The Scruzol can be magnetically stored onto metal surfaces, the classic example being storing the tool onto a fridge door where it's easy to find.

2) The large central ring magnet used to retain bits in their storage slot also generates a strong magnetic field along the Scruzol's axis and this engenders a strong magnetic attraction to screws in both of the bit-sockets, thereby eliminating the need to manually hold a screw onto the bit while starting it into a work piece.

3) Since all the stored bits are magnetically attractive, loose screws and small metal parts can also be conveniently stored onto the side of the handle. Thus, when power-driving, screws can be stored onto the rotating handle for easy transfer onto the active screwdriver bit when needed.

One drawback inherent to the Scruzol's power-driven mode of operation is that it requires the user to furnish a full-sized electric drill that has a chuck capable of grasping the outside of the Scruzol's shaft (which typically is made of 3/8" hexagonal stock in order to provide enough material to form a'/4" socket in its ends). Due to this requirement to carry and store the heavy and bulky drill, a Scruzol's power-driven mode may not be convenient for users performing tasks which require an easily transported and compact tool.

It is therefore desirable to devise an electric power tool that is capable of driving a Scruzol and is significantly more compact than a conventional electric drill.

It is also desirable that this new power tool be capable of storing the Scruzol integral to its structure while not in use and that the bulk, weight and storage footprint of the two mated tools be kept to a minimum.

It is also desirable that this new power tool be able to apply high torque to threaded fasteners, even while using a very small battery and motor to actuate the Scruzol.

It is also desirable that is new power tool be easy to recharge its battery and that the charger occupy a minimum amount of space.

It is also desirable that is new power tool be able to be easily carried, hands-free, by the user and that its Scruzol portion may be quickly decoupled from its drive unit portion for use as a manual screwdriver or else quickly coupled to it for use as a power-driver.

It is also desirable that this new power tool illuminate the work area when needed and be usable as a general-purpose flashlight when not being used as a screwdriver.
Summary of the Invention An electric drive unit for a "Scruzol" (a "Multi-Bit Dual-Mode Screwdriver For Either Manual Or Powered Actuation"). Said drive unit is comprised of a substantially cylindrical, handheld housing, said housing having a hexagonal scabbard axially formed into one end for storage of a Scruzol's shaft. A hexagonal drive stub protrudes axially from said housing's opposite end and is configure for mating into a Scruzol's handle-end bit-socket for powered rotation of its shaft-end bit-socket. Said drive stub is powered by an internal electric motor, an internal battery and external motor control switches. A circular shroud protrudes from said housing to surround said drive stub such that the drive unit may be stored vertically onto a flat horizontal surface. The concave area surrounding said drive stub includes electrical contacts for mating onto an external battery charger.
Said battery charger may include side-prongs that plug directly onto a standard electrical wall outlet, thereby providing both electrical power and wall support for both charger and drive unit being charged. Said charger has an upper surface formed such that the vertically oriented drive unit mates directly onto electrical contacts for charging. A belt clip may be provided to facilitate carrying both the drive unit and its stored Scruzol. Lighting means may also be provided proximate to said drive stub for illumination of said Scruzol while in its powered mode of activation or else for general purpose use as a flashlight while said Scruzol is stored in its scabbard.

Brief Description of the drawings.

Preferred embodiments of the invention will now be described by way of example with reference to the accompanying drawings, in which;

Figure 1 illustrates my previous "Scruzol" invention (CA 2,541,354) adjacent to its electric drive unit and withdrawn from its storage scabbard;

Figure 2 illustrates the Scruzol of Figure 1 when stored in its scabbard;

Figure 3a illustrates a Scruzol withdrawn from its storage scabbard for manual use;
Figure 3b illustrates the Scruzol of Figure 3a transferred onto the power unit's drive stub and being used to power-drive a screw;

Figure 4 illustrates the Scruzol and its power unit being used to manually apply high torque onto a screw;

Figure 5 illustrates the power drive unit ready for mating onto its electrical-outlet-mounted battery charger;

Figure 6 illustrates the battery charger mated to the drive unit when removed from the wall socket of Figure 5;

Figure 7 illustrates a power drive unit embodiment that includes a belt clip which enables the user to carry a Scruzol conveniently for either manual or powered operation;
Figure 8 illustrates the inclusion of LEDs onto the drive unit for illuminating the power-driven Scruzol or for independent use as a general-purpose flashlight.

Detailed Description.

Figure 1 illustrates Scruzol 1 positioned axially above its power drive unit 2. The Scruzol is comprised of handle 8 formed about shaft 3, said shaft having a handle-end magnetic bit-socket 4 and a shaft-end magnetic bit-socket 5, each for operative retention of an active screwdriver bit 7. Six longitudinal storage slots 9 retain up to a twelve screwdriver bits 6, each of said bits having a tip configured for a particular screwdriving task.
Central ring magnet 10 retains said spare screwdriver bits in their respective storage slots until needed and also provides the three auxiliary functions described above under "background".
Scruzol 1 may be transformed from a manually-driven screwdriver into an electrically-driven power-driver simply by transferring bit 7 from bit-socket 5 to bit-socket 4 and then grasping shaft 3 in the chuck of a conventional electric drill (not illustrated).

Electric drive unit 2 is comprised of housing 11, inside of which are a rechargeable battery 15 and an electric motor drive mechanism 16 (both not visible however both battery and motor drive are well known to those practiced in the art). Housing 11 has a substantially cylindrical shape as shown however considerable shape variation may be used to make it comfortable to grasp and manipulate. For typical users, said cylindrical housing 11 measures approximately 6" x 1.5" (for reference: Figures 2, 4 and 7 are drawn at a scale of 1:1). Switches 13 and 14 cause clockwise and counterclockwise motor direction for either tightening or loosening screws when said Scruzol is being power-driven as described below. Discrete switches may be provided as shown however alternate switch layouts (such as a "rocker") may be implemented. Other suitable switch configurations include: a toggle switch to control the motor's direction of rotation and a separate pushbutton switch to turn the motor on and off. Alternatively, a pushbutton and a toggle switch may be combined into a single motor control.

Scabbard hole 12 is formed axially into the battery-end of housing 11 and is sized and shaped to snugly receive shaft 3 such that Scruzol 1 can be partially stored within its power drive unit 2. Scabbard hole 12 is shaped for a snug fit onto the sides of inserted shaft 3. A spring biasing means or a compliant friction pad is typically formed onto one or more facets inside scabbard hole 12, thereby insuring a smooth friction fit between shaft and scabbard. Said scabbard is deep enough that the entire shaft and a mounted bit can be contained within it, thereby storing both the ready-to-use Scruzol and its drive unit within a minimum space.

Scabbard hole 12 typically requires that internal battery 15 have a doughnut-shape that accommodates inserted Scruzol shaft 3. Housing 11 must have a sufficiently strong internal structure surrounding scabbard hole 12 that substantial torque applied manually onto said housing is reliably transferred onto shaft 3 of Scruzol I (see Figure 4).

Figure 2 illustrates the Scruzol 1 and power drive unit 2 shown in Figure 1.
Said Scruzol's shaft 3 has been fully inserted into its storage scabbard 12 for minimal combined volume.
The two mated tools can be stood upright to minimize their storage foot print on workbench 29.

Figure 3a illustrates Scruzol 1 withdrawn from hexagonal scabbard hole 12 formed in the "battery end" 15 of electric drive unit 2. It's apparent in Figure 3a is that when withdrawn from its scabbard as shown, Scruzol 1 may be taken away and used for handheld, manual screwdriving tasks. It may also be taken away and used for power-driven screwdriving tasks by first gripping its shaft in the chuck of a conventional electric drill (not illustrated) and then inserting a screwdriver bit into magnetic bit-socket 4.

Figure 3a also illustrates details of the power drive unit's exposed "motor end" 16.
Internal motor 16 is directly coupled to drive-stub 17 which rotates in response to user commands from control switches 13 and 14. Drive stub 17 is a length of hexagonal steel rod which emulates the shank of a standard screwdriver bit (which is typically 1/4" hex rod).
Said drive stub's length is sufficient that either bit-socket 4 or bit-socket 5 of Scruzol 1 can seat fully onto it. The small magnet in the bottom of said magnetic bit-sockets thereby contacts drive stub 17 and retains Scruzol 1 onto drive stub 17 with sufficient force to prevent it from falling off, even when hanging vertically from the drive unit during use.
Drive stub 17 may be recessed into the motor-end of housing 11 by provision of circular shroud 19, thus forming dished end face 20. Positive and negative battery charging contacts 18a and 18b are positioned within dished end 20 and used for recharging the power unit's internal battery as described in detail below. The height of circular shroud 19 is equal to or greater than the length of drive stub 17, thereby permitting drive unit 2 to be stored vertically onto its circular contact plane as shown in Figure 2.

Figure 3b illustrates the Scruzol of Figure 3a transferred onto the drive unit's motorized drive stub 17 and being used to power-drive a screw 21. The Scruzol's handle-end bit-socket 4 will typically be used for coupling to the drive unit as shown because this configuration provides the greatest reach to drive screw 21 into cramped quarters. The shaft-end bit-socket 5 may however on occasion be used for coupling the Scruzol onto its drive unit because this configuration provides rear clearance for the user to access all of the bits 6 that are stored magnetically within handle 8. Note that extra screws may be stored magnetically onto the side of the Scruzol's rotating magnetic handle 8. For aesthetic reasons, the curvature of dished end surface 20 may closely follow the curvature of the Scruzol's domed handle. Alternatively, the curvature of dished end surface 20 may be relatively open as shown. The more open curvature of surface 20 shown in Figure 3b provides surface greater area for implementing the charging and lighting features described below and shown in Figures 5 and 8.

Figure 4 illustrates how the electric drive unit's storage scabbard can also be used to remedy the inherent weakness of internal battery 15 and motor 16: in order to minimize the drive unit's volume, said internal battery and motor must be so small that they cannot provide sufficient torque for difficult tasks (for example: driving a large wood screw 21 into a hardwood work piece 22). In such cases, the electric drive unit's motor 16 will stall and to remedy this problem, the user can transfer Scruzol 1 from drive stub 17 back into its storage scabbard 12 as shown. This configuration will enable the user to apply sufficient manual torque onto housing 11 to continue rotating bit 7 and thereby complete the difficult screwdriving task.

Figure 5 illustrates how the internal battery 15 contained within drive unit 2 may be conveniently recharged using battery charger 23 and without the use of an external electrical connection cable. Standard electrical prongs located on the back of charger 23 (shown in Figure 6) plug directly into electrical wall outlet 24, thereby providing both electrical power and mechanical support. Drive stub 17 on said drive unit fits freely into storage bore 25 on said charger, thereby permitting domed surface 30 on said charger to mate against the corresponding dished surface 20 on said drive unit.

To mate electrically as well as physically, contacts 26a and 26b on charger 23 connect to corresponding contacts 18a and 18b on drive unit 2. Other embodiments of suitable electrical contact between charger 23 and battery 15 are within the scope of the present invention. For example: instead of the discrete positive and negative contacts shown in Figure 5, a single coaxial plug containing both positive and negative contacts might be located near storage bore 25 with similar effect. In a preferred embodiment of the charging contacts; dome 30 on charger 23 and its matching dished surface 20 on power unit 2 conceal inductive charging means that "invisibly" transfer power from said charger into said battery (as is commonly used to charge electric toothbrushes). As shown in Figure 8, inductive charging provides a cleaner appearance and prevents contamination of exposed electrical contacts. Inductive charging also eliminates the need for the user to carefully align discrete electrical contact points when placing the electric drive unit onto its battery charger.

Figure 6 illustrates the drive unit and battery charger of Figure 5. Drive unit 2 is shown mated onto battery charger 23 and thus ready for charging once said charger's standard electrical contact prongs 31 are fitted onto standard wall outlet 24. To illustrate the versatility of the present invention, Scruzols la and lb are also shown being used independent of their drive unit 2. Scruzol 1 a is poised for manually driving screw 21 a while Scruzol lb is shown conveniently stored onto the metal contained in drywall corner 32. Also evident is that the magnetic attraction of Scruzol handle 8 also enables small metal parts such as screw 21 b to be conveniently stored.

Figure 7 illustrates an embodiment of electric drive unit 2 that includes belt clip 33. When hooked onto the user's belt (not illustrated), the drive unit is thereby transformed into a belt scabbard for Scruzol 1. Belt clip 33 enables more convenient and versatile use of the invention, for example: while working up a ladder, the user can perform other tasks while keeping the Scruzol easily accessible for when manual screwdriving tasks arise. If and when power-driven screwdriving tasks arise then the drive unit 2 can be unclipped and used as illustrated in Figures 3a and 3b.

The belt clip 33 shown in Figure 7 is formed monolithic to housing 11 of electric drive unit 2 however other belt clip fabrication techniques and configurations are within the scope of the present invention. For example: a removable clip may be provided that uses either screws or spring clips to attach to housing 11. Removing the belt clip might provide a smoother grip onto the drive unit when it's used in the high-torque manual screwdriving mode shown in Figure 4. Another desirable belt clip configuration, that provides greater comfort when the user is seated, is the rotatable and detachable style of belt clip that is commonly used for cell phone belt clips.

Figure 8 illustrates an embodiment of the electric drive unit 2 that includes one or more light sources to illuminate the Scruzol when it's being used in low light conditions. Each light source 34 is typically a high intensity Light Emitting Diode (LED) that is positioned near the perimeter of shroud 19, thereby permitting its light to shine past a mounted Scruzol and illuminate said Scruzol's active screwdriver bit (see Figure 3b).
The light source(s) 34 are powered by battery 15 and may be connected for activation by motor control switches 13 and 14. When no Scruzol is mounted onto drive stub 17, said light sources may be activated without motor rotation by means of a separate electrical switch (not illustrated), thereby enabling the electric drive unit to more efficiently and silently serve as a general-purpose flashlight.

It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention that are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination.

Claims (6)

1) An electric drive unit for rotating a "Scruzol" (a "Multi-Bit Dual-Mode Screwdriver For Either Manual Or Powered Actuation"), said electric drive unit comprised of: a substantially cylindrical, handheld housing containing a battery-powered motor drive and, a hexagonal drive stub projecting from one end of said housing, said drive stub being axially coupled at one end to said motor drive and formed for coupling into a bit-socket on said Scruzol.

2) The electric drive unit of claim 1, further comprising a "scabbard hole"
formed into the opposite end of said housing from said drive stub, said scabbard hole being formed for frictional retention of the shaft of said Scruzol.

3) The electric drive unit of claim 1, further comprising a battery charger having standard electrical prongs projecting from a vertical side surface for engagement into a standard electrical wall socket and means formed onto the horizontal upper surface of said charger for electrical engagement to the battery of said electric drive unit.

4) The electric drive unit of claim 1, further comprising a belt clip attached to said housing proximate to said scabbard hole.

5) The electric drive unit of claim 1, further comprising a circular shroud formed onto the end of said housing and surrounding said drive stub to a height equal to or greater than said drive stub's protrusion distance from said housing.

6) The electric drive unit of claim 1, further comprising one or more light sources formed into the drive-stub end of said housing, adjacent to and sufficiently distant from said drive stub for light to shine past said coupled Scruzol.