CA3082670A1 - Drill-powered ebike - Google Patents

Abstract

An articulated bracket that clamps a pendulously-hanging friction-wheel onto the frame of a pushbike to convert it into an Ebike. The axial driveshaft of the pendulous friction-wheel is gripped in the chuck of a cordless drill and the pendulum's swing geometry is configured with respect to the one of the pushbike's tires to cause the friction-wheel to be forced against the tire when the drill is activated, thereby propelling the pushbike forward. A torque-arm mounted on the pendulum prevents counter-rotation of the drill's housing. To enable the rider to control power to the driven wheel, a handlebar-mounted cable mechanism actuates the drill's trigger. In a preferred embodiment, the friction-wheel includes an internal ratchet mechanism that allows friction-free pedalling of the pushbike while the drill's trigger is released.

Description

Drill-powered Ebike Background of the invention Field of the Invention This invention relates to electric-assist bicycle propulsion systems and more particularly to an articulated bracket that pendulously affixes a drill-powered friction-wheel between a pushbike's frame and one of its tires, thereby converting the pushbike into a friction-drive "Ebike".
Description of the Prior Art The "pushbike" (bicycle) was one of the first inventions to be patented so there exists a wide variety of granted IP as well as many non-patented but innovative commercial products;
furthermore, there are a variety of relevant hobbyist projects that have been documented on YouTube. Together, they provide a broad scope of prior art that is relevant to the present invention.
A significant milestone in bicycle evolution was the introduction of electric-assist propulsion to ease the rider's physical burden. Various motorized drive configurations have been devised that enable two broad categories of Ebike propulsion systems. Mechanical-drive systems apply torque to the pushbike's rear-wheel drive gear-train. Friction-drive systems use a friction-wheel to apply torque directly onto one of the pushbike's tires and thereby counter-rotating it forward.
In 1899, John Schnepf's US patent 627 066 disclosed one of the earliest friction-drive electric-assist propulsion systems; since then, many mechanical-drive and friction-drive Ebikes have been proposed. Three examples of relevant friction-drive Ebike patents are:
Battlogg et al. (US
5,816,355), Dennis (US 5,842,535) and Olsommer (US 9,975,602 B2); each of these Ebike configurations utilize one or more motorized friction-wheels, held against the pushbike's front or rear tire to propel it forward.
Various friction-drive kits for converting a pushbike into an Ebike are also on the market. Below is a list of relevant websites:
https://www.alizetibikes.com/
https://revolutionworks.com/
http://www.hiddenpower.co.kr/international/ (also see W02010134793) https://www.rubbee.co.uk/
http://www.velogical-engineering.com/
https://sites.google.com/site/commuterbooster/home These prior art friction-drive conversion kits are constrained by the need to provide a dedicated battery, a dedicated motor/controller and a dedicated drive mechanism. This results in a complex apparatus that is expensive to manufacture; furthermore, it cannot be used for any other purpose than to propel the bicycle. Ideally, all or part of an Ebike conversion kit could be Date Recue/Date Received 2020-06-09 used for other applications when not being used for transportation, thereby improving the kit's versatility and cost-effectiveness.
Concurrent with the evolution of both bicycles and Ebikes, battery-powered tools, such as cordless drills, have experienced ongoing improvements to both their battery life and their electromotive efficiency. The major manufacturers now produce a "family" of workshop and industrial cordless tools as well as a variety of cordless home maintenance accessories. To improve their cost-effectiveness, all members of each company's cordless power-tool family are designed to share the same swappable battery modules.
Given the ubiquity and versatility of these swappable, cordless-tool battery packs, it would be desirable to devise a means for efficiently extending their range of applications to include powering an Ebike. Towards that end, a few fledgling efforts have been made to utilize a cordless drill to propel a bicycle. Below is a list of articles and videos that document various "DrillBike" DIY Ebike projects that have been made to date:
https://www.asme.org/topics-resources/content/make-way-for-drillpowered-bikes https://makezine.com/projects/the-drill-rod/
https://www.youtube.com/watch?v=gC3rB9f7DaU
https://www.youtube.com/watch?v=_eWK4RdjCwc https://www.youtube.com/watch?v=grcskPrbsvl https://www.youtube.com/watch?v=7N-1A-RLLdQ
https://www.youtube.com/watch?v=0Z8dFIVNrY8 https://www.youtube.com/watch?v=mGu4iFK9y3U
https://www.youtube.com/watch?v=MxmkrXXKAJU
https://www.youtube.com/watch?v=fXGirSOBaWo https://www.youtube.com/watch?v=KjeL3HbpknY
https://www.youtube.com/watch?v=vx7qYXn9drA
As is evident in the above articles and videos, the general configuration of a cordless drill makes it poorly suited for powering an Ebike. The complex or flimsy drill-holding strategies and power-transfer strategies tried to date have resulted in scooter-type vehicles that are barely usable;
their efficiency is particularly poor when the vehicle is coasting (because the stopped drill typically acts as a brake).
The present invention rectifies the above-mentioned drawbacks in the prior art, thereby providing a simpler, more versatile and more cost-effective drill-powered Ebike. The invention in its general form will first be summarized by a concise textual description of its principal embodiments, and then its implementation will be described with reference to the drawings following hereafter. These embodiments are intended to demonstrate the principle of the invention, and the manner of its implementation. The invention in its broadest and more specific forms will then be further described, and defined, in each of the individual claims which conclude this Specification.

Date Recue/Date Received 2020-06-09 Summary Of The Invention An articulated bracket that clamps a pendulously-hanging friction-wheel onto the frame of a pushbike, thereby converting it into an Ebike capable of being powered by any cordless drill.
The protruding central driveshaft of the friction-wheel is gripped in the drill's chuck; when rotated by the drill, the pendulum's cam geometry with respect to one of the pushbike's tires causes the friction-wheel to be forced against the tire, thereby propelling the tire and pushbike forward. An anti-torque arm mounted on the pendulum blocks counter-rotation of the drill's housing which, if left unchecked, would spin the entire drill and thereby prevent power transfer into the pushbike's driven tire. To enable the rider to control power to the driven wheel, a handlebar-mounted cable mechanism actuates the drill's trigger. In a more energy-efficient embodiment, the friction-wheel includes an internal ratchet mechanism freewheels to enable friction-free pedalling or coasting while the drill's trigger is released.
Note regarding definitions and nomenclature:
The scope of the term "pushbike" includes all "Human Powered Vehicles" (HPVs) that are propelled over the ground by a user "pushing" with one or more of their limbs.
While the ubiquitous two-wheeled "Bicycle" is the most common pushbike, the three-wheeled "Tricycle" is also propelled as a "pushbike"; the friction-drive mechanism of the present invention can be configured to apply electric-assist to both two-wheeled and three-wheeled pushbikes. Similarly, the "Unicycle", the "Skateboard", the "Kickbike" and the "Pedicar" are HPVs that have (more limited) potential for being fitted with the present invention. The invention might therefore be titled "Drill-powered HPV" or "Drill-powered Pushbike" however the chosen "Drill-powered Ebike"
title relates to its most socially relevant application: that of converting existing bicycles into cost-effective "Ebikes". Similarly, the title term "Drill-powered" is does not cover the full scope of the invention; several of its embodiments do not utilize a drill for electromotive power. To include those embodiments, a title such as "Electric-assist Pushbike" or "Electric-assist HPV" might be more apt. The descriptive text herein should be interpreted in light of the broadest definition of the invention's title terms.
Detailed summary of the minimum viable embodiment In its essence, the invention is an articulated bracket that enables frictional propulsion of a pushbike's tire by means of a drill-driven, pendulously-hanging friction-wheel; the bracket and friction-wheel mechanism is comprised of the following 5 member elements:
1) A support-spar member The articulated bracket is anchored to the pushbike's frame by its substantially horizontal support-spar member, which is clamped at one end onto a substantially vertical frame member.
The clamped-on spar-end is anchored using a suitably configured clamp that is integrated into one end of the spar-shaped member, thereby providing robust support for the pendulous propulsion system which hangs from its opposite end. When clamped onto the pushbike's seatpost, the support-spar is cantilevered over the rear tire, thereby enabling a rear-wheel-drive Date Recue/Date Received 2020-06-09 embodiment of the invention. The support-spar member may also be configured for clamping onto the pushbike's rotatable handlebar or steering assembly and cantilevered forward over the front tire, thereby enabling a front-wheel-drive embodiment.
More concisely: this element of the articulated bracket is a substantially horizontal support-spar member having one of its ends configured for clamping onto a substantially vertical frame member of the pushbike; the spar's opposite end being cantilevered over the driven tire and configured to include a transverse pivot axle for carrying the upper end of a swingable pendulum-spar member.

2) A pendulum-spar member The support-spar member is cantilevered over the friction-driven tire and carries a side-mounted pivot bearing axle near its unanchored outer end. A side-mounted pendulum-spar member (also referred to herein as the "swingarm") hangs and swings freely from the pivot bearing it shares with the support-spar. When configured in this manner, the pendulum spar swings in a plane that is adjacent to the plane of the driven wheel. The upper end of the pendulum-spar carries a pivot bearing fixture which enables articulation within the bracket and the pendulum's lower end carries an anti-friction bearing, through which the driveshaft-axle of a drill-driven friction-wheel is journaled. The friction-wheel is thereby side-mounted to the pendulum-spar's lower end such that its plane swings coincident with the plane of the driven tire. Instead of side-mounting, a centrally-hinged pendulum-spar may also be used, provided it includes a forked lower end that centrally carries the friction-wheel onto the driven tire (as described for the embodiment of Figure 20).
To enable the articulated bracket to fit the widest possible range of pushbike frame sizes and styles, its support-spar member and/or its pendulum-spar member may include adjustment means for tailoring their effective length to fit a particular pushbike. For example: one or both spars might be comprised of two shorter lengths of tubing, with one fitting inside the other for telescopic adjustability and with clamping fixations that fix the spar's effective length.
Alternatively, an adjustable spar might be comprised of two short spar lengths joined by a robust threaded rod; once the end sections are adjusted to a desired effective length, lock-nuts on the threaded section are used to secure the assembly.
More concisely: this element of the articulated bracket is a pendulum-spar member configured at its upper end for swinging from the transverse pivot axle and configured at its lower end with a bearing for rotatably carrying the axle of a friction-wheel that the pendulum-spar can swing so that the center of its rim rests against the center of pushbike's driven tire tread.

3) A drill-driven friction-wheel The friction-wheel has a high-friction contact surface around its rim and a coaxial driveshaft for rotating it. The driveshaft is journaled inside the pendulum-spar member's lower bearing such that its high-friction contact surface is aligned onto the pushbike's driven tire. To enable it to Date Recue/Date Received 2020-06-09 effectively propel the tire, the lengths of the support-spar and pendulum-spar are chosen such that the friction-wheel swings eccentrically into contact against the front face of the driven tire when it is counter-rotated, thereby propelling the tire forward. Lowering or raising the height of the support-spar will adjust the angle of the pendulum-spar somewhat as its friction-wheel rolls up or down the front face of driven tire's tread. To propel the Ebike in the desired direction (forward), its pendulum-spar must also be angled forward; in this configuration, gravity will cause the spar's end-mounted friction-wheel to swing backward and downward until it rests against the driven tire.
Once the pendulum's eccentric geometry is set, counter-rotating the friction-wheel causes it to forcefully swing into the tire; the greater the torque on the friction-wheel, the more it will "bite"
onto the tire for improved traction. This "cam" action is caused by the friction-wheel's geometric interference with the tire; since energy input is mechanically constrained by the articulated bracket and the tire, the only way that rotational force applied to it by the drill can equalize is for the free-rolling driven wheel to rotate forward and thereby propel the pushbike. This pendulous cam geometry will automatically force friction to increase under difficult loading situations, for example: when the rider is accelerating up a hill using a powerful drill.
The pendulum-spar's automatic anti-slippage function can be adjusted by raising or lowering the support-spar and thereby adjusting the mechanical advantage of the constrained pendulum-spar member (governed by the spar's changing angle with respect to the driven wheel). For example, in rainy weather, the user might raise the support spar member slightly so as to apply more friction onto the driven tire. Raising it too much will cause the friction-wheel to apply so much leveraged pressure that it will compress the tire enough to climb over it and escape rearwards (and thereby instantly loose all friction). In dry conditions, lowering the support-spar member will increase the pendulum-spar's inclination angle, thereby resulting in both slightly less wheel traction and slightly better energy efficiency (both due to less tire compression).
Fine tuning both the pendulum-spar's forwardly inclined angle and the driven-tire's air pressure will typically result in smooth operation. In cases where the spar-angle and/or the tire pressure are poorly adjusted, intermittent heavy acceleration may result in a "chattering" type of power application (due to the friction-wheel bouncing on the tire). To help control those cases of poor adjustment, a spring loaded fixture (such as a hairpin spring) may be added to the articulated bracket's pendulous pivot-joint, thereby adding a spring-biased contact pressure onto the tire. If a pressure-biasing spring is provided, it typically is used in conjunction with the freewheeling embodiment of the friction-wheel.
In a preferred embodiment of the friction-wheel, its central driveshaft protrudes from both sides, thereby providing a somewhat balanced leverage of the shaft as bending forces are applied to its support bearing in the pendulum-spar. On one side of the wheel, the driveshaft extends far enough out to provide journaled support for the wheel (inside the pendulum-spar's lower shaft bearing) and on the opposite side of the wheel, it extends far enough out to form a stub that the Date Recue/Date Received 2020-06-09 chuck of a cordless drill can be securely tightened onto. In an alternate embodiment of the friction-wheel, its driveshaft extends asymmetrically from only one side. In this configuration, the pendulum-spar bearing is journaled on the same side of the friction-wheel as the spar. A
further extension of the shaft (beyond its journaled portion) is gripped by the chuck of the drill;
thereby placing both the pendulum-spar and the drill on the same side of the friction-wheel.
This more asymmetric driveshaft embodiment exerts higher bending stress due to its longer lever arm to the wheel it drives. An asymmetric driveshaft will also force the drill to be mounted further outboard from the Ebike.
Note regarding drills. Some special-purpose power-tools are configured with a 90-degree gearbox between their motor and their rotating tool head. The use of a 90-degree "right-angled drill" (or a 90-degree adapter) will enable the drill chuck to grip onto the friction-wheel's driveshaft while providing a narrower overall width of the drive mechanism (because the drill's bulky main housing will be oriented upwards instead of outwards). The use of a 90-degree drill is therefore somewhat desirable however the increased cost and complexity of adding a right-angle bend to the drivetrain makes it less easy to practice than using a simpler and more widely available inline drill. If narrow width is an important operational requirement, then a right-angled drill can be used however it will entail customizing an appropriately-shaped anti-torque arm to constrain it (see item #4 below).
In both the symmetric and asymmetric embodiments of the driveshaft, when the drill is actuated, torque applied to the friction-wheel causes counter-rotation of the vehicle's driven tire and forward propulsion of the Ebike. In both embodiments, the forward portion of the driven tire's tread supports the downward force exerted by the weight of the drill and its gripped friction-wheel as the pendulum-spar attempts to swing them back towards hanging vertically. That gravitational contact force onto the tire establishes the wheel's initial level of friction; once torque is applied by the drill's motor, the frictional bond onto the tire increases.
More concisely: this element of the articulated bracket is a friction-wheel having a high-friction outer rim and a coaxial driveshaft, the driveshaft having a first portion configured as an axle for journaling in the lower pendulum-spar bearing and a second portion configured as an extension that is grippable by the chuck of a cordless drill.

4) An anti-torque-arm that prevents drill counter-rotation The anti-torque arm is affixed to the pendulum-spar and extends outward to just past the outer extremity of the cordless drill's pistol grip, thereby blocking the drill from counter-rotating in response to the friction-wheel being powered. Since all of the drill's weight is carried by the drill chuck's grip onto the friction-wheel's driveshaft, the rider can quickly attach or detach the drill from the pushbike; simply by tightening or loosening the chuck.

Date Recue/Date Received 2020-06-09 More concisely: this element of the articulated bracket is an anti-torque arm affixed to the pendulum-spar that reaches past the attached cordless drill's housing to block it from counter-rotating as it's chuck rotates the friction-wheel against the driven tire.

5) A cable-controlled throttle To enable the rider to control the amount of electric-assist being provided by the drill, a handlebar-mounted throttle is cable-connected to a drill trigger-actuator. The mechanical actuator depresses on the drill's spring-loaded trigger in response to the rider pulling on a control lever or actuating a twist-grip control (similar to the controls used to actuate a pushbike's brakes or to change its gears). The drill's trigger may be actuated by a cable actuated pushrod mechanism affixed through the pendulum-spar. Alternatively, the drill may be remotely throttled by configuring the control cable's inner wire as a noose that tightens around the pistol grip to squeeze its trigger.
More concisely: this element of the articulated bracket is a handlebar-mounted throttle that enables the Ebike's rider to remotely depress the trigger of an attached drill's trigger.
A freewheeling embodiment that improves energy efficiency Due to the high internal gear ratio in a typical cordless drill, when its motor is stopped, its chuck becomes very hard to turn. Since a blocked friction-wheel would produce significant drag on the driven tire, in another embodiment, a ratcheting mechanism is located inside the friction-wheel, where it acts as a freewheeling one-way clutch that selectively couples its driveshaft to its friction surface. The internal freewheel enables the friction-surface to be driven backwards as the driven wheel turns forward, thereby improving energy efficiency while the pushbike is coasting or being propelled solely by the rider's pedalling effort.
A cargo-carrying embodiment In another embodiment, the support-spar member described above includes a rear extension that goes beyond the support-spar's side-mounted pivot bearing. The far end of the extended support-spar includes a trailer hitch configured for pulling a cargo trailer.
The trailer-hitch can only be used on rear-wheel-drive Ebike configurations, however, the extended support-spar on either a rear-wheel drive or front-wheel drive configuration may be used to carry cargo directly. To provide cargo space, the elongated support-spar serves as a backbone from which side panniers are affixed. When side panniers are provided for carrying cargo, one of the panniers also serves to contain the cordless drill, thereby protecting it from the elements and concealing it from view. The pannier containing the drill includes a side aperture that enables the drill to actuate the friction-wheel; the pannier may also be lined with sound absorbing material to attenuate drill noise that might detract from the rider's user experience.

Date Recue/Date Received 2020-06-09 A long-distance commuting embodiment Modern cordless drills are available with high efficiency brushless motors and large capacity Li-ion batteries (100 - 200 watt-hours). A single battery pack used for typical electric-assist commuting might provide a range of approximately 10-20 kilometres.
To enable longer commutes or for pulling cargo over hilly terrain, the rider will profit from carrying one or more spare batteries that can be swapped onto the drill as needed. To facilitate quick battery changes, the pushbike's water-bottle mounts can be repurposed to carry spare batteries. To enable this feature, a special-purpose rack is provided on the frame that includes battery bays that mimic the clip-on mechanism used by the drill.
A front-wheel-drive embodiment that swings from the pushbike's handlebar A potentially useful characteristic of pushbikes is that their stem and handlebar structure maintains a fixed steering relationship with the front wheel. Typical handlebar stems are vertically adjustable within the frame's head-tube and fork-steering tube assembly. Their inverted L-shape presents a substantially horizontal upper portion that grips the handlebar at its forward end is joined at its rearward end to a substantially vertical lower portion that forms part of the pushbike's frame. This stem/handlebar/wheel configuration presents an opportunity to utilize the handlebar as a transverse pivot from which the pendulum-spar can be hung (instead of hanging it from a pivot formed on the side of a support-spar). To practice this handlebar-mounted embodiment, a pendulum-spar is configured with an upper-end bearing that hangs from and rotates about the handlebar near its central engagement with the stem. The pendulum-spar's lower end is configured as described above so that it can rotatably support a friction-wheel that a drill counter-rotates to propel the front wheel forward.
A hybrid embodiment that complies with all classes of Ebike legislation Many jurisdictions require that an Ebike only be capable of being electrically assisted while it is being simultaneously propelled by the rider's pedalling effort. Where such regulations exist, three classes of legal Ebike are generally defined as follows:
Class 1 Ebikes: are pedal-assist only and have a maximum assisted speed of 20 mph.
Class 2 Ebikes: have a maximum assisted speed of 20 mph, but may be throttle-controlled.
Class 3 Ebikes: are pedal-assist only and have a maximum assisted speed of 28 mph.
The "minimum viable embodiment" described further above can be easily configured to qualify as a Class 2 (throttle-controlled) Ebike; simply by providing a small enough diameter friction-wheel that the converted pushbike cannot exceed 20 mph when powered by a typical cordless drill (-1500 RPM). However, in order to qualify as either a Class 1 or a Class 3 Ebike, the minimum viable configuration must be augmented with electronic components for measuring the Ebike's speed and the rider's pedalling effort as well as means for using that real-time data to modulate the level of electric-assist being applied to the Ebike's driven wheel.

Date Recue/Date Received 2020-06-09 Since a cordless drill integrates its battery, motor and trigger-modulated motor control into a single handheld housing, it cannot be used as a Class 1 or Class 3 power source (because there's no way to limit speed and insure that the rider is pedalling). To achieve Class 1 or Class 3 compliance requires that, in addition to the articulated bracket and friction-wheel components of the minimum viable embodiment, the Ebike conversion kit must also include a cadence-sensor mounted on the pushbike's crank assembly, a speed-sensor mounted on one of its wheels, a handlebar-mounted electronic throttle and an electronic motor-control unit that uses all three sensors to modulate power from an included battery to an included electric motor, the motor having its output shaft directly affixed to the input side of the friction-wheel's driveshaft.
Using internal circuitry and algorithms, the motor controller regulates the amount of current being supplied to the motor in response to the rider's observed pedalling activity and/or their throttle commands.
Preferably, the battery used to power this embodiment's electric motor is also compatible with a cordless drill or similar power tool (a leaf-blower, a jigsaw, a vacuum cleaner etc), thereby maximizing the Ebike's versatility. If standardized tool batteries are used (including spare batteries) they may be mounted on the pushbike's frame using a suitably configured mounting bracket that includes both mechanical clips and electrical contacts. The electrical contacts are wired to the motor-control unit; they mimic the contracts on corresponding and compatible cordless power tools. The battery mounting bracket may also include multiple battery docking stations that enable batteries to be connected in series thereby increasing the voltage of current flowing to the motor.
In another embodiment, a smartphone clamped onto the handlebar is included and wirelessly connected to the speed and cadence sensors. A software application on the smartphone uses the sensors to display real-time performance data.
The fully-compliant hybrid embodiment has the same main structural components as the minimum viable embodiment described above (a clamped-on support-spar, a swinging pendulum-spar and a motor-driven friction-wheel). The configuration of its torque arm is somewhat modified in shape so that it's outer end can be affixed directly onto the motor's housing to prevent counter-rotation.
The fully-compliant embodiment may also make use of direct-drive hub motors mounted inside the friction-wheel thereby eliminating the need for a torque arm altogether (because the hub-motor's central spindle is gripped immovably at the lower end of the pendulum-spar). One appropriate hub motor for this direct-drive friction-wheel configuration is made by LinearLabs Inc. (see Huntstable, US 9,419,483).
Upgrading a Class-2-only Ebike to a fully-compliant Ebike The substantive difference between the fully-compliant embodiment (that conforms to Class 1, 2 and 3 requirements) and the minimum viable embodiment (that qualifies only as a Class 2 Date Recue/Date Received 2020-06-09 Ebike) is that in the fully compliant embodiment, the drill's motor, its battery, its motor-controller (the trigger), and its coupling to the friction-wheel (its chuck) are replaced by four discrete components. The commonality of the main structural) components enables a cost-effective upgrade path between the two embodiments.
To take advantage of this potential upgrade path, a pushbike owner would initially purchase the minimum viable embodiment. Once they have gained experience with the drill-powered embodiment, they could purchase an upgrade kit that adds the extra components needed for Class 1 or Class 3 operation' as well as perhaps purchase additional enhancements (such as a smartphone display, trailer hitch, panniers and extra batteries and battery-holding brackets).
Tricycle, Kickbike and other HPV embodiments "Human Powered Vehicle" is a broad category that includes the two-wheeled "pushbikes" used in the illustrative examples described above. The same friction-drive propulsion can also be attached to other types of HPV. For example, provided that the Drill-powered Ebike's friction-drive is mounted on a symmetrically centered (front or back) wheel, it can also be used to propel a tricycle. A single drive unit can be mounted on the front wheel of a tricycle that has two rear wheels; alternatively, one can be mounted onto the rear wheel of a tricycle that has two front wheels. This vehicle configuration is particularly useful for elderly or partially-disabled riders who might otherwise not be able to pedal their "Adult-trike" with sufficient strength or stamina.
Another style of HPV that can profit from being fitted with the present invention is called the Halfbike TM (see it at www.halfbikes.com). The Halfbike combines aspects of a tricycle, a unicycle, a penny-farthing, a pushbike and a skateboard; the result is a folding HPV that is pedalled like a pushbike and steered by transferring body weight like a skateboard (also see "Folding pedal powered tricycle", by Angelov et al, USD774969S1). The Halfbike is a fun to ride adult tricycle and, when folded, its compact wheelbase enables it to be easily stored or transported on public transit. While those are attractive features, the geometry of this HPV
makes ergonomic compromises that render it poorly suited for climbing steep hills. The Halfbike is therefore a good candidate for upgrading with an appropriately configured electric-assist mechanism of the present invention.
Both the conventional (pedalled) pushbike and the (pedal-less) "Kickbike" are two-wheeled HPVs however a Kickbike is propelled forward by the rider standing on a platform and pushing on the ground with one foot (instead of standing on a pushbike's pedals while actuating them to rotate the driven wheel). The Kickbike is therefore also a good candidate for being fitted with the present invention; eliminating the pushbike's pedal-driven drivetrain makes the HPV lighter, simpler and easier to use than a similarly-upgraded pedal-bike.
Like the two-wheeled Kickbike (compared to the two-wheeled pedal-driven bicycle), the Halfbike tricycle described further above would profit from being stripped of its pedal-drive and propelled mainly by the drill-powered friction-drive of the present invention. To practice this modified Date Recue/Date Received 2020-06-09 Halfbike configuration, its pedal-crank drive mechanism is eliminated and replaced by a standing platform together with a front-wheel friction-drive. An additional benefit of simplifying the structure in this manner is that having a standing platform enables the rider to step towards the rear of the platform, thereby shifting it center of gravity and thereby reducing the danger of the short-wheelbase Electric Vehicle capsizing forward during hard braking.
Eliminating the Halfbike's pedal-powered drivetrain would reduce its weight and complexity however including human pedal-power input enables the rider to get healthy exercise and extend battery life. An optimal configuration might therefore be to add both electric-assist to a pedal-powered Halfbike and also add a narrow standing platform that does not interfere with rotation of its pedal crank. An additional benefit is that retaining its pedal crank drivetrain would qualify it as a legal Ebike in most jurisdictions.
List of figures Figure 1 illustrates a typical pushbike that has been converted into an Ebike by mounting the present invention onto its seatpost, together with a cordless drill.
Figure 2 is a large-scale view of Figure 1 illustrating left-side detail of the Ebike's drill-driven propulsion mechanism.
Figure 3 is a large-scale view of Figure 1 illustrating right-side detail of the Ebike's drill-driven propulsion mechanism.
Figure 4 illustrates both a non-freewheeling friction-wheel and a freewheeling friction-wheel that improves energy-efficiency.
Figure 5 is an exploded view showing a convenient way to configure a freewheeling friction-wheel such as the one shown in Figure 4.
Figure 6 is an oblique view of an elongated embodiment of the friction-drive mechanism that includes a trailer hitch.
Figure 7 illustrates the embodiment of Figure 6 being used to tow a trailer.
Figure 8 illustrates an embodiment with rear cargo panniers, one of which also houses the Ebike's drill-driven propulsion mechanism.
Figure 9 illustrates the embodiment of Figure 1 with the addition of racks for carrying additional batteries that can be swapped onto the drill as needed to extend the Ebike's range.
Figure 10 illustrates a lightened embodiment using round tubular spars.

Date Recue/Date Received 2020-06-09 Figure 11 is another lightened embodiment using square tubular spars.
Figure 12 is a large-scale view of two drills, each showing a different style of trigger-actuator.
Figure 13 illustrates a front-wheel drive embodiment.
Figure 14 illustrates another front-wheel drive embodiment.
Figure 15 is a large-scale view of the front-wheel drive embodiment in Figure 14.
Figure 16 illustrates an embodiment that accommodates the legal requirement in some jurisdictions that an Ebike only be operable when the rider is pedalling.
Figure 17 is a large-scale view of Figure 16 showing implementation details.
Figure 18 illustrates a two-wheel-drive embodiment that is compliant with all legal requirements.
Figure 19 illustrates the front-wheel- drive propulsion system of Figure 18 in which the pushbike's handlebar serves as the pendulum-spar's pivot.
Figure 20 illustrates the front-wheel-drive propulsion system of Figure 19 in which its electric motor is housed inside the friction-wheel and serves as its hub.
Figure 21 illustrates a "Halfbike" hybrid tricycle that has been converted into an electric-assist vehicle by adding the friction-drive mechanism of the present invention.
Figure 22 is a large-scale view of the hybrid tricycle shown in Figure 21.
Figure 23 illustrates a "Kickbike" that has been converted into an Electric Vehicle by adding the present invention to propel its front wheel forward.
Figure 24 illustrates a foldable, three-wheeled Electric Vehicle powered by the friction-drive mechanism of the present invention.
Description of the Figures Figure 1 illustrates a typical pushbike 1 that has been converted into an Ebike by clamping articulated bracket 2 onto it. For clarity in this overview figure, drivetrain details have been omitted (spokes, pedals, chain, cables and other small hardware details). The relevant parts of the pushbike in this figure are its seat 6 and seatpost 9, which are telescopically adjustable inside its seat tube 4 by tightening seat clamp 5. Rear tire 11 mounted on rear wheel 10 is Date Recue/Date Received 2020-06-09 frictionally propelled forward by rotational force applied by cordless drill 3. Handlebar 7 steers the Ebike and is used to mount a throttle (not shown) that actuates the trigger of drill 3.
Figure 2 is a large-scale view of Figure 1 illustrating left-side details of the articulated bracket and its associated mechanical components. The bracket's substantially horizontal support-spar member 19 is rigidly affixed at its forward end to seatpost 9 using integral clamp 20. In this example, clamp 20 is comprised of slotted bore 21 which is accurately sized to slip over seatpost 9; when pinch-bolt 22 is tightened the support-spar becomes securely cantilevered over the driven wheel 10 and its driven tire 11.
Several other configurations of a suitable clamp 20 will be evident to those practiced in the art.
Figure 10 illustrates one example that uses a pair of V-notched clamping jaws squeezed onto seatpost 9 at its four corners by screws 22. Another variant of this spar-clamping mechanism (not illustrated) is to hinge the two clamping jaws along one side and tighten them together on the opposite side; ideally, by using a cam-clamp similar to the seat-clamp 5 shown in Figure 10.
In Figure 2, the cantilevered support-spar 19 includes a side-mounted pendulum pivot-axle located near its unsupported end. The pivot-axle shaft typically has a fixation portion 24 (visible inside its support-spar) and a bearing-axle portion 26 that projects from the side of support-spar 19 to rotatably engage through its pivot-bearing 25 of pendulum-spar 23 (shown in Figure 3).
The pendulum-spar also carries a bearing near its lower end that rotatably supports a driveshaft portion of friction-wheel 18. The lower bearing (35 in Figure 3) enables the friction-wheel 18 to rotate freely in the same plane as the pushbike's tire 11.
Support-spar 19 is shown clamped onto seatpost 9 at a height that is appropriate for effective Ebike propulsion. Instead of hanging vertically, pendulum-spar 23 is swung forward due to its captive friction-wheel 18 resting against the forward side of driven-tire 11.
In this configuration, if friction-wheel 18 is counter-rotated to force forward rotation of tire 11, the swinging contact geometry forces the pendulous friction-wheel into to ever greater frictional contact as the tire's rolling resistance increases.
Note that, while Figure 1 shows a simplified pushbike having a rigid front fork and a rigid rear wheel ("hardtail") suspension, the traction of friction-wheel 18 onto driven tire 11 will not be significantly disturbed if it were mounted on a pushbike equipped with a compliant wheel suspension of one or both wheels. If a suspended driven wheel 10 hits a bump in the road that varies the distance between tire 11 and support-spar 19, then pendulum-spar 23 will simply swing a bit further to compensate for the change in drivetrain geometry.
To impart propulsive force into friction-wheel 18, cordless drill 3 is affixed by its chuck 12 onto a driveshaft stub that projects from one side of the friction-wheel. The drill's chuck is driven by its internal motor 15, which is controlled by the variable-speed drill-trigger 14 located on the drill's Date Recue/Date Received 2020-06-09 handle portion 13. The cordless drill's battery 16 is typically removable so that a freshly-charged replacement battery can be swapped into handle 13 as needed.
To enable rider-controlled rotation of the drill's motor 15 and its attached friction-wheel 18, trigger 14 is mechanically actuated by a throttle control that is mounted on or near the pushbike's handlebar. A suitable throttle control (not illustrated) can be comprised of a conventional brake lever, repurposed to actuate the inner cable of jacketed control cable 42.
Other suitable cable actuators can be fashioned using an off-the-shelf gearshift lever or twist-grip (again not illustrated). In this embodiment of a drill trigger-actuator, cable 42 is routed from the handlebar back to an off-the-shelf, 90 degree "brake cable noodle" that anchors the cable's outer casing and routes its inner control cable through an aperture in pendulum-spar 23. The drill's trigger is actuated by pushrod 44 that slides though the pendulum-spar in response to the control cable pulling on pushrod-actuator-bracket 49. Several other styles of drill trigger-actuator are shown in Figure 11.
While pushbike 1 is being propelled as an Ebike, the torque resistance of the its driven wheel 10 will create an equal and opposite torque in friction-wheel 18. To prevent that counter-torque from spinning the entire drill (instead of inducing forward motion), anti-torque arm 37 is provided. Anti-torque arm 37 is an elongated rigid member affixed at one end to pendulum-spar 23 and sized long enough to extend just past drill-handle 13, thereby blocking it from rotating.
To prevent drill-housing rotation on both directions, anti-torque arm 37 will typically provide blockage onto both sides of drill-handle 13. One or more shim-pads 41 may be provided so that drill 3 can be easily affixed onto friction-wheel 18 without any side-play as power is intermittently applied.
Figure 3 is a large-scale view of Figure 1 illustrating right-side detail.
Articulated bracket 2 is clamped to seatpost 9 and functions as described above. This right-side view better illustrates pendulum-spar 23; its upper bearing 25 and lower bearing 35 are typically sealed ball bearings that provide low friction and high rigidity as the pendulum swings from pivot-axle 26 and the drill-driven axle 34 of friction-wheel 18 turns to counter-rotate tire 11 forward.
Drill-trigger 14 is actuated by pushrod 44; typically, via a cushioning pad 50 that spreads the pressure and maintains grip on the trigger. The inner control wire 48 of jacketed control cable 42 is pulled through aperture 47 in pendulum-spar 23, thereby forcing bracket 49 to slide pushrod 44 through bearing-bore 45 to actuate trigger 14.
To achieve both structural robustness and bi-directional blockage of drill-handle 13, torque-arm 37 may be configured as an H-shaped assembly as shown, thereby creating an outboard docking space into which the drill's pistol-grip handle slides as its chuck is secured onto protruding driveshaft stub of friction-wheel 18 (see Figure 4). Bridge support 39 imparts rigidity to front and rear torque-blocking members 37 that are secured to the pendulum-spar 23 with fasteners 38 and to bridge-support 39 with fasteners 40. To adjust the H-shaped torque-arm for a sliding fit of the drill handle 13 of a particular drill, shim-washers may be inserted between the Date Recue/Date Received 2020-06-09 arms 37 and their respective mating surfaces. If a particular drill has a slim handle, adhesive shim cushions 41 may be applied to the inner side of the docking space to provide a snug fit.
Figure 4 illustrates two configurations of a friction-wheel suitable for being a drill-driven component of the drill-driven Ebike. Friction-wheel 18a is a monolithic structure comprised of a central core portion 36, an outer friction-surface portion 32, an axial driveshaft-stub portion 33 and an axial bearing-support portion 34. In this example, the wheel's central core portion 36 includes a series of optional holes that reduce its weight. Its friction surface 32 is textured rubber however various high-fiction surface finishes may be used; see knurled surface 32 on wheel 18B and the abrasive wheel-finish shown in Figure 11. Driveshaft stub 33 may have a hexagonal cross-section to facilitate secure gripping in the drill's chuck.
The axial driveshaft's bearing-support portion 34 extends far enough to fully seat within the pendulum-spar's lower bearing.
Friction-wheel 18b is an alternate embodiment of the friction-wheel; in this case, an assembly which includes an off-the shelf bicycle freewheel 27 (detailed in Figure 5).
The incorporated freewheel acts as a one-way clutch that selectively transmits torque from the driveshaft's input stub 33 out to its friction surface 32.
Figure 5 is an exploded view of the freewheeling friction-wheel 18b shown in Figure 4. It illustrates a convenient and cost-effective way to add a one-way clutch that allows friction-free coasting and thereby improves the Ebike's energy efficiency. An off-the-shelf "BMX" style bicycle freewheel 27 is incorporated onto the assembly's central core portion 36 so that its internal ratchet pawls apply power unidirectionally between driveshaft 33 and friction surface 32.
The enlarged driveshaft adapter portion 29 includes an outer thread 58 that matches the standard hub-thread 59 inside freewheel 27 (this thread is typically 1.37" x 24 TPI). Once the driveshaft and freewheel have been joined by screwing thread 58 into thread 59, the freewheel's sprocket teeth 28 are placed flush against the friction-wheel's central core portion 36 and secured there by affixing retention-ring 30 against the opposite side of the sprocket using a plurality of retention screws 31. The retention screws are spaced-apart for reaching through the sprocket's teeth and into corresponding threaded holes in core-portion 36.
Figure 6 is an oblique view of an elongated embodiment of the friction-drive mechanism that includes a trailer hitch. Support-spar member 19 includes an extended portion 51 that reaches past the location of the pendulum-spar's pivot-axle 26. The extension can thereby provide support for trailer-hitch 52, which in this example is simply a vertical bore that is configured for mating with a corresponding pin on the hitch mechanism of a cargo trailer when needed.
Various other trailer-hitch configurations will be obvious to those practiced in the art.
Figure 7 illustrates the extended support-spar embodiment of Figure 6 when it is being used to tow a trailer. In this example, trailer 53 is a folding dolly that includes a swivelling pin style of Date Recue/Date Received 2020-06-09 hitch 54 that mates through the hitch aperture 52 near the rear end of support-spar extension 51. Once the hitch pin 54 has been secured to the converted Ebike 1 (typically using a cotter-pin), its rider can transport a substantial load of cargo 55 with greater ease.
Figure 8 illustrates another embodiment that enables pushbike 1 to haul extra cargo. Support-spar 19 and its trailer hitch extension 51 provide a stable foundation for affixing one or more cargo panniers 60. To enable drill 3 to rotate friction-wheel 18 at the end of pendulum-spar 23, the inboard wall of pannier 60 has appropriately-shaped apertures (not visible) through which the drill's chuck and the anti-torque arm operate. Panniers 60 may also include lids (not illustrated) that protects cargo from theft and exposure to the elements. The pannier 60 that houses the drill 3 may also be lined with a layer of sound-deadening material to attenuate noise from the drill which might otherwise detract from the rider's user experience.
Figure 9 illustrates the embodiment shown in Figure 1 after it has been equipped with one or more extra batteries that extend the Ebike's range. Pushbike 1 is fitted with articulated bracket 2 such that its pendulously suspended friction-wheel 18 is counter-rotated by drill 3 against tire 11 to propel the converted Ebike forward. Drill battery 16 is powering the vehicle and when its charge becomes depleted, one of freshly charged batteries 56 (mounted on storage racks 56) is swapped onto the drill to continue a long journey.
Figure 10 illustrates a light-weight embodiment similar to the one shown in Figure 1. Support-spar 19 is formed using a hollow tube to reduce weight. Pendulum-spar 23 is also lightened, as are its welded upper and lower bearing shells 63 and 64. Instead of throttling the Ebike using a pushrod style of drill-trigger actuator sliding through the pendulum-spar (as shown in Figures 2 and 3), a "noose-style" of trigger actuator 65 is actuated by control lever 43 (shown conceptually mounted onto a conceptual handlebar 7). Jacketed cable 42 routes its inner actuating cable 48 via a standard bicycle "cable noodle" 46 such that it wraps around the trigger and pistol-grip of drill 3 and is secured into a noose that can be tightened to depress the drill's trigger as needed (see Figure 12 for details).
Seatpost clamp 20 is comprised of a pair of V-grooved jaws that adjust automatically to grip onto all of the common diameters used for seatpost 9. V-grooved jaw 62 is welded to support-spar member 19. V-grooved jaw 61 is corner-bolted to jaw 62 using threaded fasteners 66;
when tightened, they force seatpost 9 to be firmly gripped along its 4 tangential contact lines.
Figure 11 illustrates another lightened embodiment that uses square tubes to form the spars.
Support-spar 19 Is clamped to seatpost 9 as described above. Its rectangular cross-sectional shape facilitates fabrication of compact bearing fixations for hanging pendulum-spar 23 and friction-wheel 18. Noose-style drill-trigger actuator 65 is shown with an optional sheath 68 that flexibly distributes the force of inner control wire 48 as the noose tightens onto drill-trigger 14.
Throttle-cable yoke 67 is used to form the noose (see detail in Figure 12).

Date Recue/Date Received 2020-06-09 Figure 12 is a large-scale view of two drills (3a and 3b), each drill illustrating one of two different "noose-style" drill-trigger actuators (65a and 65b). Each these drill-trigger actuators is connected by inner control wire 48 and its outer control cable sheath 42 to a cable-actuating throttle located on the Ebike's handlebar (7 in Figures 1 or 10). In each embodiment of this style of trigger-actuator, an optional "cable-noodle" 46 may be used to guide the inner control through a sharp 90 degree bend towards trigger 14, while simultaneously constraining the ferrule-end of cable sheath 42. The cable-noodle wire-guide 46 is merely a convenient, sharply-curved extension of the outer cable 42; if it is omitted, then the coaxial cable 42, 48 is simply routed towards the trigger along a wider curve. Two styles of control cable-yoke (67a and 67b described below) may be used to form a noose that tightens around trigger 14 to variably control the Ebike's speed.
Referring to the right-hand drill (3b), one end of cable-yoke 67b receives and constrains the ferrule end of outer cable sheath 42 (either directly or from its sharply curved extension 46) .
The yoke's other end accepts and constrains a nipple formed on the end of inner wire 48 (its end-nipple 69 is shown about to be affixed through a slot in yoke 67a). Yoke 67b rests against the drill's pistol-grip 13, thereby enabling wire 48 to wrap around trigger 14 and be locked into the yoke's far end to form a noose that pulls on trigger 14 in response to throttle actuation.
Similarly, on the left drill 3a, cable yoke 67a (a shorter version of 67b) is positioned adjacent to the side of pistol-grip 13. Inner control wire 48 exits one end of the compact yoke, encircles the pistol-grip 13 and is secured into a noose by seating its end-nipple 69 through a slotted yoke aperture. Pulling inner wire 48 through its sheath 42, thereby tightens the noose and actuates the trigger.
These two examples of a noose-style trigger-actuator are shown with an optional inner-wire low-friction sleeve 68. If present, the wire-sleeve protects the drill's pistol-grip and trigger from wire-abrasion. It also reduces actuator friction that might otherwise prevent the trigger from easily springing back out when the throttle is released.
The configuration of both of the "noose-style" trigger actuators 65a and 65b results in a halving of the distance that the trigger will move in response to the distance that the inner cable 48 is pulled at the handlebar. This 2:1 ratio results in a throttle action that can more easily make small throttle adjustments. For example a trigger that has a range of 1/2"
will require the actuator on the handlebar to pull the cable a full inch to achieve full throttle. While that type of slow throttle response is generally desirable, other configurations can be implemented that provide a faster throttle response (for example, Figure 3 illustrates a 1:1 throttle actuator).
Figure 13 illustrates a two-wheel drive embodiment of the invention that includes dual propulsion systems 2a and 2b; it can be used for increased power and better traction on slippery terrain. In this example, pushbike 1 is a "cruiser-style" bicycle that includes a high-rise handlebar 7, thereby providing user 80 with a more relaxed riding posture. To further improve Date Recue/Date Received 2020-06-09 the Ebike's suitability for comfortable commuting, fenders 78 may be provided however doing so will prevent frictional contact between friction-wheel 18b and rear tire 11b.
To rectify the fender's impediment to frictional contact, fender-aperture 79 is provided.
Handlebar stem 70 presents a tall enough vertical portion that clamp 20 can be affixed onto stem 70 in much the same manner as the clamp 20 is affixed onto seatpost 9 (as shown in Figure 10). If a particular handlebar stem does not provide sufficient vertical tubing for affixing the support-spar's clamp then its height can often be adjusted upward as needed; in some cases, an aftermarket "Stem Extender" will be needed to provides a good clamping surface.
A second instance of the drill-powered propulsion system 2a can be fitted to the front of a suitably configured pushbike as described above for a rear-wheel drive 2b. The rider's right hand can actuate throttle 43a to regulate power output of drill 3a while a left-hand throttle can actuate the rear-mounted drill 3b. Note that, since handlebar 7, stem 70 and front tire 11a are all rigidly connected and turning in unison, the Ebike's steering performance is virtually unaffected by the front-mounted system 2a.
Note that the two-wheel drive version of Figure 13 (and 14) easily be configured with only a front-wheel drive propulsion system. Front-wheel drive on a pushbike raises the possibility of expanding the scope of the invention's applications to include FWD propulsion of other types of HPVs, such as tricycles (see Figure 21) and even kickbikes (see Figure 22).
Note also that, when configuring a front-wheel-drive system, extra care must be taken to provide a pendulum-spar that is long enough to prevent its friction-wheel 18 from compressing tire 11 far enough that its pendulum-spar can swing past its closest point of alignment onto the center of the wheel. If that geometric scenario were to occur then the friction-wheel would be driven into a violent "swing-through" collision against the pushbikes head-tube. Note too that if the pushbike has a telescopic front fork (not illustrated) then the pendulum-spar's length must also be long enough to prevent swing-through when the fork is fully extended.
Provided that the pendulum-spar is long enough to prevent a swing-through failure, normal telescopic action of a front fork will be automatically accommodated as gravity causes the pendulum-spar to swing back and forth as it its friction-wheel responds to vertical motion of the suspended front tire.
Figure 14 illustrates a simplified front-wheel drive embodiment 2b that exploits the existing support structure of a pushbike's handlebar 7 and stem 70. A dual-drive Ebike is shown in which the rear articulated bracket 2a includes pendulum-spar 23; it hangs on and rotates about the pivot axle 26, which is affixed to pushbike 1 via support-spar 23, clamp 20 and seatpost 9.
The front articulated bracket 2b is considerably simplified by utilizing the pushbike's handlebar 7 to serve the same function as pivot axle 26 for suspending pendulum-spar 82.
Stem 70 also serves a dual function; by supporting the handlebar/pivot axle 7, it effectively acts as as support-spar 19; together, these equivalent-functionality components provide a sturdy pivot-axle with Date Recue/Date Received 2020-06-09 correct support geometry for enabling the rotatably attached pendulum-spar to drive the front wheel (see Figure 15 for details).
Note that the rear cordless drill 3a is mounted onto the pushbike's left side while the front cordless drill 3b is mounted onto its right side. The example serves to illustrate that the Drill-powered Ebike can be configured for either left-side drive or right-side drive; the main difference in a mirror-imaged system is that drill's direction of rotation is reversed.
To advance Ebike 1 forward, drill 3a is set to rotate clockwise while drill 3b is set to rotate counterclockwise.
Figure 15 is a large-scale view of the front-wheel drive embodiment 2b shown in Figure 14.
Stem 70 includes a forward-reaching portion that clamps onto the middle of handlebar 7, thereby presenting two transverse handlebar portions adjacent to the left and right sides of stem 70; these handlebar portions can serve as a pivot-axle for a suitably configured pendulum-spar.
To do so, pendulum-spar 82 includes a slip-bearing clamp 83 at or near its upper end that is configured for rotational engagement onto handlebar 7 adjacent to stem 70, thereby eliminating the need for a purpose-built support-spar 19 and pivot-axle 26 (shown in the rear-wheel-drive portion of Figure 14).
In simplified, front-wheel-drive-only embodiment of Figure 15, the lower end of pendulum-spar 82 is configured as described above: i.e., it carries an anti-friction bearing that supports the axle of friction-wheel 18b so that the high-friction rim can be counter-rotated against front wheel 11b by drill 3b. Since bearing-clamp 83 only experiences slight rotational forces, it does not require the kind of high-speed anti-friction bearing needed to sustain propulsive force through friction-wheel 18b. The slip-bearing clamp 83 shown in Figure 15 is the most basic embodiment: it consists simply of an accurately bored hole through pendulum-spar 82, that closely matches the diameter of the thickened, central portion of handlebar 7 (typically 25.4 mm or 31.8 mm). In some cases, the user's handlebar will not have a suitable amount of straight and exposed central tubing, in which case the Ebike conversion process will entail fitting one with an acceptable tube profile.
The illustrated slip-clamp bearing 83 enables the upper end of pendulum-spar 82 to be fitted over the handlebar from one end and slide into place against stem 70, where it acts as a plain bearing onto the handlebar, thereby converting the handlebar into a pivot-axle for pendulum-spar 82. To prevent the pendulum-spar 82 from drifting away from the stem 70 and upsetting the traction of its friction-wheel onto the tire, a small locking protrusion 84 is typically affixed to the handlebar, adjacent to the slip-bearing's opposite side (not visible). In a more sophisticated embodiment, an adjustable-friction slip-bearing clamp (not illustrated) might be fashioned in a manner similar to the V-grooved clamp 20 (shown in Figure 14) that is used to affix support-spar 19 to seatpost 9. If an adjustable slip-clamp 83 is fashioned, it preferably includes a plastic lining that slides easily over the handlebar as the pendulum-spar swings slightly back and forth.
This will enable the user to eliminate any side-play of the friction-wheel while still allowing the pendulum-spar to easily swing slightly back and forth as needed.

Date Recue/Date Received 2020-06-09 Another embodiment of a suitable slip-clamp configuration (not illustrated) combines elements of the front-wheel-drive shown in Figure 13 with the one shown here in Figure 15. Instead of utilizing the handlebar tube directly as a pivot axle for rotating the pendulum-spar 82, a compact hinge-half fixture is clamped tightly onto the handlebar, adjacent to stem 70.
The upper end of the pendulum-spar includes a machined hinge-half that engages into its mate on the handlebar and a hinge-pin secures the two halves together. Depending on the stem and handlebar configuration of the pushbike being converted to an Ebike, the hinged slip-clamp embodiment may be somewhat easier to install than the simplest one described above. An added advantage is that, if the hinge is formed at some distance from its handlebar clamp (essentially forming a laterally-offset support-spar), rotating this elongated clamp to different angles about the handlebar will adjust the effective overall distance to the friction-wheel and thereby provide a useful way to fit the hinged pendulum-spar onto various sized pushbikes. The added geometric degree of freedom and its attendant adjustability may also be useful for repositioning the pendulum-spar to prevent interference with the pushbike's brake control levers and cables.
Trigger actuation: The FWD (front-wheel drive) configuration shown in Figures 14 and 15 reveals yet another way that the trigger of cordless drill 3 can be remotely actuated from handlebar 7. The trigger actuators described further above (for actuating both FWD and RWD
embodiments) depend on use of a coaxial control cable; the actuator shown in Figure 3 uses a remote, cable-operated pushrod 44 to depress trigger 14. The actuators shown in Figure 12 use a remote, cable-operated noose to depress the trigger. Since the FWD
pendulum-spar 82 swings directly from (or near) the handlebar, the potential exists for implementing a short, manually-actuated mechanical linkage directly onto the trigger, thereby eliminating the need for a remote coaxial control cable.
To implement this type of FWD-specific trigger-actuator, the pushrod (44 shown in Figure 3) may be reconfigured for direct actuation from the handlebar via a "rocker-actuator" member (not illustrated). The rocker-actuator extends from the pushrod-end up the pendulum-spar, over a fulcrum-bearing that retains the rocker in place; the rocker terminates at its upper end with a suitably formed handle portion for actuation by the rider's throttle-hand.
Alternatively, a FWD-specific trigger-actuator might be fashioned using a single "trigger-lever"
(also not illustrated).
The trigger-lever is also a rocker-style member; at one end it is bent to impinge directly against the drill's trigger and at it other end it is bent to provide a hand-grip that is conveniently-near the handlebar. A pivot bearing affixed to the anti-torque arm (possibly coincident with the anti-torque arm spacer 39 of Figure 3) journals and retains the trigger lever to act as a fulcrum, thereby enabling the rider to manually actuate the lever's upper end to depress the spring-loaded drill-trigger at the other. To enable the trigger-lever to fit various handlebar configurations, it is typically made of stiff but bendable material such as aluminum, thereby enabling the rider to fine-tune its bent shape for optimal actuation of their drill.

Date Recue/Date Received 2020-06-09 Figure 16 illustrates an embodiment that conforms to the legal requirement in some jurisdictions that an Ebike's assist mechanism only be operable while its rider is pedalling. In order to comply with such legislation, instead of relying on a cordless drill for its electromotive propulsive force, this embodiment utilizes a standard off-the-shelf electric motor 71 and couples it directly onto the driveshaft of friction-wheel 18. A compact anti-torque arm 72 bridges over the friction-wheel to anchor the motor to the pendulum-spar, thereby enabling the use of separate components that ensure the Ebike meets local regulations for rider-participation and top-speed.
To insure that the converted Ebike meets Class 1, 2 and 3 requirements (the class definitions are summarized further above), motor controller 73 is electrically connected to motor 71, battery 56, electronic throttle 78, pedal-cadence sensor 74 and wheel speed-sensor 76.
Wheel-speed sensor 76 is activated by a magnet 77 mounted on a wheel 10 and pedal-cadence sensor 74 is activated by crank-mounted magnet 75. Throttle 78 is typically a rheostatic twist-grip mounted on handlebar 7. The two speed sensors and the throttle are typically hardwired to the motor controller; alternatively, the two sensors may transfer data wirelessly to simplify installation. The motor controller includes logic circuitry that enables it to use the three electrical signals in accordance with the local speed and rider-participation regulations. The computed real-time power application data is used to regulate the high-power current flow from battery 56 to motor 71. A smartphone may be affixed onto handlebar 7 to display such as trip information and battery charge condition (not illustrated).
Battery 56 is typically the same as used to power a cordless tool (such as the drill 3 shown in Figure 14). Battery carrier 57 facilitates mounting multiple batteries and can include circuitry for joining them in series to produce higher voltage. For example, a popular cordless tool battery configuration provides 18 volts; if carrier 57 connects them in series then motor 71 may be chosen from one of the many 36 volt off-the-shelf products on the market.
Additional batteries may be mounted on the exterior of support-spar 19 or frame-mounted as shown in Figure 9.
There may be sufficient room inside of hollow support-spar 19 to neatly contain the electronic components of motor controller 73, this compact electronics-packaging strategy is particularly suitable when using the extended-spar shown in Figure 8.
Figure 17 is a large-scale view of Figure 16 showing details of the components used for upgrading the drill-driven (Class 2 only) embodiment of Figure 11 to a fully-compliant (Class 1, 2 and 3) Ebike. Seatpost-clamp 20, support-spar 19, pendulum-spar 23 and friction-wheel 18 are major structural components that are common to both the compliant and non-compliant embodiments. This presents the opportunity for a pushbike owner to start off by fitting the most basic drill-driven Ebike kit to power their converted pushbike. Once they have tried Ebiking with a drill-powered (Class 1) version, they can later choose to upgrade it to either Class 1 or Class 3 operation. To do so, they used pre-drilled mounting holes in the basic support-spar and pendulum spar to add components. Motor 71 is added to replace the drill (using an adapter-collar). The large torque-arm 37 shown in Figure 11 is removed and replaced by a compact torque-arm 72. Motor-controller 73 is then bolted on, together with its connected speed sensor, Date Recue/Date Received 2020-06-09 cadence sensor and throttle. Swappable batteries 56 are also mounted and wired to complete the conversion.
Figure 18 illustrates a two-wheel-drive embodiment that also complies with Class 1, 2 and 3 Ebike requirements. It resembles the embodiment shown in Figures 13 and 14 except that the cordless drills 3a and 3b have been replaced by separate electric motors 71a and 71b.
Handlebar throttles 43a and 43b control electromotive power being applied to front and rear tires lla and llb using shared electronic components (motor-controller 73 and its associated batteries, wiring and speed sensors).
Figure 19 illustrates the front-wheel- drive propulsion system 2b of Figure 18 in which the pushbike's handlebar 7 serves as the upper pivot-axle that bearing 83 of pendulum-spar swings on. The forward-reaching portion of stem 70 serves the same function as the support-spar 19 shown in Figure 13. This front-wheel drive system may be used as a stand alone system provided the shared electronic components shown in Figure 18 are included (its batteries, sensors and motor controller). To provide a well-configured handlebar for engagement with slip-bearing clamp 83, a precision-machined aftermarket handlebar may be provided for retrofitting to pushbike 1.
Figure 20 illustrates a front-wheel-drive embodiment similar to the one shown in Figure 19. In this embodiment, hub motor 85 serves the same function as drill 3b in Figure 15 or the electric motor 71b shown in Figure 19. Unlike electric motor 71b, which requires that an anti-torque arm 72b constrain the motor housing from turning so that its output shaft is free to rotate the attached friction-wheel 18b, the central shaft of hub motor 85 is firmly gripped in a clamping bore located near the lower end of pendulum-spar 82. The hub motor's internal winding's can thereby exert electromotive force to turn the motor's high-friction rim 32.
The upper slip-bearing clamp 83 enables the pendulous motor 85 and friction-surface 32 to engage onto and fractionally drive tire 11. This configuration eliminates the need for a separate anti-torque arm and results in a generally more compact device.
The illustrated hub motor 85 has a central shaft that projects from only one of its two side (in this case, the far side) however many suitable hub motors have grippable shaft portions on both sides, thereby providing a symmetrical load distribution. If a symmetrical hub motor is being used, then a second pendulum-spar (not illustrated) may be added to handlebar 7 to grip the motor symmetrically (with a spar on each side of the handlebar stem).
Similarly, pendulum-spar configurations such as those shown in Figures 1 and 13, can be reconfigured for symmetrically carrying a hub motor (instead of a drill-driven friction-wheel). To do so, a forked pendulum-spar (not illustrated) hangs centrally from the support-spar's outer end; a centrally located hinge joins the two spars and each side of the swinging fork grips onto a side of the hub motor's shaft.
The pendulum-spar 82 is typically hollow and therefore able to house the electronic motor controller 73 that regulates the output of motor 85 in response to electronic throttle 43. If a Date Recue/Date Received 2020-06-09 second pendulum-spar is present, as described above, then it will add to the available space for containing electronic components so batteries may also be stored therein.
Preferably, swappable power-tool batteries 56 are carried on the pendulum-spar in battery cradles 57.
Slip-bearing clamp 83 may be a simple bore fitted over handlebar 7 as shown.
Alternatively, a quick-release hinged opening (not shown) enables the user to quickly detach the entire propulsion system 2 from handlebar 7 of pushbike 1, thereby enabling the Ebike to be parked while its propulsion system is carried away by the user for safekeeping or for battery charging.
To reactivate the Ebike, the quick-release slip-bearing clamp is refitted to handlebar 7 and the control wire contact from throttle 43 is reattached to controller 73.
Note that, since the hub motor 85 fully occupies all of the space bounded by its high-friction rim 32, no room is available to incorporate a freewheel as shown in Figure 5. This lack of a mechanical freewheel would render the drivetrain inefficient when coasting (due to the magnetic drag of the motor). To counteract that energy-loss problem, the motor-controller's electronic circuit and algorithm is used to provide just enough power to match the speed of friction-surface 32 to its driven tire 11 when throttle 43 is shut off, thereby minimizing any drag effects during coasting or while the rider is pedalling with the throttle closed.
Figure 21 illustrates a "Halfbike" tricycle 86 that has been converted into an electric-assist vehicle by adding a friction-drive mechanism 2 of the present invention. The unmodified Halfbike TM (see US D774, 969 S) is tricycle-style HPV that is steered by its user transferring their body weight from side to side, thereby causing the spring-loaded steering truck 87 to pivot left or right; its steering operates in much the same was as that of a skateboard (see videos of it at www.halfbikes.com). Halfbike 86 is comprised of a tall handlebar stem 88 joined to a pair of frame rails 91 by pivot clamps 89 and locking clamps 90, thereby enabling handlebar 7 to be selectively folded down towards the tricycle's rear wheels for compact storage or transport. A
conventional pedal-crank drivetrain 92 enables a standing rider to propel wheel 10 forward.
To convert the illustrated pushbike 86 into an electric-assist vehicle, drill-driven friction-drive mechanism 2 is affixed to the HPV's handlebar stem 88 using a lockable spar-pivot fixture 97 see detail in Figure 22). Once drive unit 2 has been mounted with correct orientation of its articulated bracket (19 and 23), drill 3 rotates friction-wheel 18 against tire 11 to propel the tricycle's front wheel forward. The trigger of drill 3 is actuated by throttle lever 43 acting through coaxial cables 42 and 48 (partially drawn). Brake lever 95 similarly actuates a drum or caliper-type brake to stop the vehicle as needed. An optional rear footboard 94 may be provided to help the user counterbalance the forward-capsizing moment experienced under heavy braking.
A second footboard 92 may provided to enable the user to rest both of their feet off of the pedal-crank while the vehicle is cruising solely under electric power.
Figure 22 is a larger-scale view of the drill-powered HPV shown in Figure 21.
To enable the friction-drive's support-spar 19 to be affixed to folding handlebar stem 88, pivot-fixture 98 is Date Recue/Date Received 2020-06-09 provided to join the stem's left and right sides together by a shaft, about which the forward end of support-spar 19 is journaled to form a rotatably and slideably articulated joint. Any movement of this articulated joint during drill-powered operation would result in the loss of traction between friction-wheel 18 and tire 11. To prevent that malfunction from occurring, locking-pin 97 fits snugly through aligned holes in the spar and shaft, thereby immobilizing the support-spar 19 with respect to stem 88 and tire 11 (in much the same manner as clamp 20 immobilizes support-spar 19 with respect to stem 70 and tire 11 in Figure 13).
As described above (for non-folding embodiments), the forward inclination and fixed geometry of the freely-swinging pendulum-spar 23 enables it to leverage the rotational force from drill-driven friction-wheel 18 onto tire 11 and thereby drive it forward. Drill 3 is prevented from being counter-rotated by anti-torque arm 37 and its trigger 14 is throttled by actuator 65, which forms a noose of inner control wire 48 that can be tightened by squeezing the vehicle's handlebar-mounted throttle lever (see Figure 12 and 43 in Figure 21).
While the drill-powered propulsion mechanism 2 is locked in its operative configuration, it will interfere with the Halfbike's folding function. The interference problem is due to the fact that, once the handlebar stem is unlocked for pivoting, its normal folding action will be arrested when the fixed support-spar 19 collides with tire 11. To alleviate that problem and permit full folding, locking-pin 97 is withdrawn so that support-spar 19 becomes free to rotate upwards around pivot-fixture 98. Friction-wheel 18 will thereby become free to roll up and over the top of tire 11 so that both the liberated support-spar 19 and its swinging pendulum 23 can articulate towards the horizontal as handlebar stem 88 is folded down fully into its compact storage configuration.
Figure 23 illustrates a kickbike-style of HPV that has been converted into an Electric Vehicle by adding the present invention as a kit to propel its front wheel forward. The drill-driven friction-drive unit 2 is virtually identical to the one shown driving the front wheel in Figure 13. The one difference in this example is that the length of support-spar 19 has been shortened to accommodate the smaller diameter of tire 11. Pendulum-spar 23 has not needed to be shortened because clamp 20 has a long range of vertical travel on handlebar stem 70.
Propulsion from drill 3 and friction-wheel 18 enable a rider standing on footboard 93 to advance with only a minimal requirement to assist propulsion by kicking their electric-assist HPV forward.
Figure 24 illustrates a foldable, three-wheeled electric-assist HPV powered by the friction-drive mechanism of the present invention. To configure this embodiment, the hybrid-powered HPV
shown in Figure 21 is simplified by replacing its pedal-crank drivetrain (92) by one or more footboards 93, 94. Without its pedal-crank drivetrain, this stripped-down version of the Halfbike might conceivably be used as a tricycle-style Kickbike however adding the drill-driven friction-drive mechanism 2 greatly improves its performance and usability.
Since the pedal-crank is absent, footboard 93 can be made wide enough for the rider to stand on with both feet. The lack of a pedal-crank drivetrain also facilitates locating a caliper brake Date Recue/Date Received 2020-06-09 underneath the footboard (not illustrated). During hard braking or a steep decent, the rider may step rearward onto footboard 94, thereby reducing the risk of the vehicle accidentally tipping forward. The rider may also choose to move one or both fee to the rear footboard simply for a change in ergonomic comfort. The large rear footboard may also be used to carry a passenger or to strap on a small load of cargo. Footboard 94 may also incorporate an aperture or projecting fixture that acts as a hitch capable of pulling a suitably configured trailer (somewhat similar to the towing configuration shown in Figure 7).
Note that this non-pedal-assisted embodiment may require extra electromotive power to propel it under heavy loads; the cordless drill 3 chosen to turn friction-wheel 18 should therefore be a high-powered industrial drill, preferably one with a wide choice of gear ratios. For example, DewaltTM makes a brushless 3-speed cordless drill and Hilti TM makes a brushless 4-speed cordless drill; mounting either of those powerful drills will enable a rider who encounters difficulty climbing a hill to switch their drill to a lower gear ratio and thereby overcome the temporary overloading problem. To deal with the extra battery drain, auxiliary battery packs 56 may be affixed to frame 91, thereby enabling spent batteries to be swapped onto the drill as needed.
Note also that both the legally-compliant embodiment shown in Figure 19 and the hub-motor embodiment shown in Figure 20 may be used in place of the drill-driven embodiments shown in Figures 21 to 24.
The foregoing has constituted a description of specific embodiments showing how the invention may be applied and put into use. These embodiments are only exemplary. The invention in its broadest, and more specific aspects, is further described and defined in the claims which now follow. These claims, and the language used therein, are to be understood in terms of the variants of the invention which have been described. They are not to be restricted to such variants but are to be read as covering the full scope of the invention as is implicit within the invention and the disclosure that has been provided herein. 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 sub-combination.

Date Recue/Date Received 2020-06-09

Claims (10)

Claims l claim:

1) An electric-assist propulsion system for a pushbike comprised of:
= a substantially horizontal support-spar member having one of its ends configured for clamping onto a substantially vertical frame member of the pushbike; the spar's opposite end being cantilevered over the driven tire and configured to include a transverse pivot axle for carrying the upper end of a swingable pendulum-spar member;
= a pendulum-spar member configured at its upper end for swinging from the transverse pivot axle and configured at its lower end with a bearing for rotatably carrying the axle of a friction-wheel that the pendulum-spar gravitationally swings into frictional contact with the pushbike's driven tire;
= a friction-wheel having a high-friction outer rim and a coaxial driveshaft, the driveshaft having a first portion configured as an axle for journaling in the lower pendulum-spar bearing and a second portion configured as an axial extension that is grippable by the chuck of a cordless drill;
= an anti- torque arm affixed to the pendulum-spar that protrudes past an attached cordless drill's housing to block it from counter-rotating as the drill's chuck rotates the friction-wheel against the driven tire;
= a handlebar-mounted throttle that enables the pushbike's rider to remotely depress the trigger of an attached drill's trigger.
O (see Figure 11 for a clarifying example)

2) The electric-assist propulsion system of claim 1 wherein the support-spar member is formed by the pushbike's handlebar stem and the transverse pivot axle is formed by the pushbike's handlebar.
O (see Figure 15 for a clarifying example)

3) The electric-assist propulsion system of claim 1, further comprising a one-way clutch mechanism between the friction-wheel's inner, grippable driveshaft extension and its outer, high-friction rim; the one-way clutch being oriented to counter-rotate the friction-wheel against the driven tire's tread to propel the pushbike forward.
O (see Figure 5 for a clarifying example)

4) The electric-assist propulsion system of claim 1, further comprising an extension of the support-spar member beyond its pivot axle, the spar extension being configured for carrying a trailer hitch fixture near its outer end that is suitable for pulling a cargo trailer.
O (see Figure 6 for a clarifying example) Date Recue/Date Received 2020-06-09

5) The electric-assist propulsion system of claim 1, further comprising an extension of the support-spar member beyond its pivot axle, the extended spar member being configured for carrying one or more cargo panniers.
O (see Figure 8 for a clarifying example)

6) The electric-assist propulsion system of claim 1, further comprising one or more battery-carrying brackets configured for carrying one or more swappable batteries that are compatible with the cordless drill used to grip and rotate the friction-wheel.
O (see Figure 9 for a clarifying example)

7) The electric-assist propulsion system of claim 1, configured for driving a first wheel of a pushbike, together with a second instance of the propulsion system configured for driving the second wheel of the pushbike.
O (see Figure 13 for a clarifying example)

8) The electric-assist propulsion system of claim 1, further comprising:
= an electronic pedalling-cadence sensor, = an electronic wheel-speed sensor, = an electronic throttle mounted on the handlebar, = an electric motor coupled to the driveshaft of the friction-wheel and having the anti-torque arm coupled to its housing = a battery, preferably a swappable cordless tool battery clipped into a compatible holder, = an electronic motor controller that integrates data from the two sensors and the throttle to control electric current flow from the battery to the motor in compliance with local Ebike performance regulations.
O (see Figure 16 for a clarifying example)

9) The electric-assist propulsion system of claim 8, wherein the electric motor is contained within the hub portion of the friction-wheel and its driveshaft is immovably gripped by the lower swingarm.
O (see Figure 20 for a clarifying example)

10) The electric-assist propulsion system of Claim 8 or Claim 9 wherein the algorithm utilized within the motor controller synchronizes the speed of the friction-wheel to the speed of the driven tire while the throttle setting is decelerating the pushbike.

Date Recue/Date Received 2020-06-09