Trikes

Field of Invention

[01] Non-tilting steering system for reverse trike.

Background of Invention

[02] It is obvious that reverse trikes are more safe and stable than bikes and conventional trikes. Reverse trikes have many mechanical advantages over conventional trikes which include stability, traction in uphills and steerability. But providing an efficient steering mechanism for reverse trikes is a challenge. In recent past many models of reverse trikes have come up in the public domain offering tilting steering system. Tilting steering system has many issues which includes traction as well as ground clearance while cornering around a turn. Non-tilting steering system for reverse trikes have drawn little attention as it is understood by majority of folks that rack and pinion steering mechanism used in cars is sufficient for the purpose. But it has its own issues which includes big reduction ratio and too complex mechanism to handle on a trike. Non-tilting steering system is provided by Newton reverse trikes. It employs pitman arm to swing the kingpin attached to spindle mounted on each of the two front steer wheels.

Technical Problem

[03] Steering mechanism of reverse trike or four wheelers have externally moving parts in the form of steer transmission rods. It may be huge disadvantage in case of uneven land mass caused during snow fall.

[04] Rotation motion is converted into translational motion which is then converted back to rotation.

[05] Non-tilting steering mechanism in Newton reverse trike, applies the steering torque on the two wheels either from the front side of the head tube or rear side of the head tube due to which force gets exerted on the head tube rearward or forward direction respectively, thus making it difficult to operate as compared to steering system for a bicycle. In bicycles steering torque applied on the wheel is symmetric along the head tube. Summary of Invention

[06] One of our objective is to provide steering system for reverse trike which is as ergonomic to operate as that of a bicycle.

To achieve this objective steering system for reverse trike is designed such that two front wheels can be transversely rotated using coupled torque. Steering torque is applied on each of the front wheels symmetrically on both ends of the axle and symmetrically on front and rear side of the steerer rods, thereby providing easy and stable maneuverability to the steering system. Head tube is proportional to the length of steerer rod to provide sturdiness to steerer rod.

Wheels can be turned by 360 degree.

[07] Rotation steering action at the handle is transmitted as steering action on the wheel

through rotation motion and is not converted into translational motion as intermediate phase.

[08] It has no externally moving parts.

Brief Description of Drawings

[09] [Fig. 1] and [Fig. 2] Side and Top view respectively of reverse trike with bevel-pinion gearset based coupled torque steering system according to this invention.

[10] [Fig. 3] and [Fig. 4] Rear and top view respectively of bevel-pinion gearset based

coupled torque steering system according to this invention.

[11] [Fig. 5] Steering mechanism according to this invention without head tubes.

[12] [Fig. 6] Central, left and right steerer rods.

[13] [Fig. 7] and [Fig. 8] Top and bottom view of central, left and right bevel-pinion gearset used as in steering mechanism according to this invention.

[14] [Fig. 9] Central, left and right wormface gearset used as in steering mechanism without head tube arms according to this invention.

[15] [Fig. 10] Blown out image of central bevel-pinion gearset

[16] [Fig. 11] Blown out image of left bevel-pinion gearset

[17] [Fig. 12] Reverse trike with rotated front wheels due to steering action by steering

system according to this invention.

[18] [Fig. 13] and [Fig. 14] Top and bottom view of central, left and right bevel-pinion

gearset used in steering mechanism with variation according to this invention. Description of Embodiments

[19] As shown in [Fig. 1] and [Fig. 3], bevel-pinion gear set based coupled torque steering system for reverse trike (1) with top tube (TT) and down tube (DT), according to this invention comprises central steering system (CSS), left wheel steering system (LSS), right wheel steering system (RSS), steer transmission mechanism (STM), steering support mechanism (SSM).

Central steering system

[20] As shown in [Fig. 1] and [Fig. 3], central steering system (CSS) consists of central

steering shaft (CST), central head tube (CHT), central gear set and central tubular cage (CTC).

[21] As shown in [Fig. 1] and [Fig. 3], central steering shaft (CST) is a straight shaft,

connected to a handle at its top, is located on the center of the front part of reverse trike.

[22] As shown in [Fig. 1] and [Fig. 3], central head tube (CHT) is a set of two sections of vertical tubes, upper section (CHT1) and lower section (CHT2) separated by distance equal to the height of central gear set with each section coaxially holding the central steering shaft using ball bearings and upper section on its rear attached to top tube (TT) and lower section attached on its rear side to down tube (DT).

[23] As shown in [Fig. 3], [Fig. 7] and [Fig. 10], central gear set consists of two coaxially parallel horizontal bevel gears (CBG1) and (CBG2) coaxially mounted on the central steering shaft, a pinion bevel gear (CPB1) on the front, a pinion bevel gear (CPB2) on the rear, a pinion bevel gear (CPB3) on the left and a pinion bevel gear (CPB4) on the right side of the steering shaft with each pinion bevel gear having axis perpendicular to the axis of steering shaft. As shown in [Fig. 3], [Fig. 5] and [Fig. 8], bottom bevel gear (CBG2) is coaxially mounted on steering shaft via ball bearing so that it is free to rotate. Top bevel gear (CBG1) is coaxially fixedly connected to the central steering shaft. As shown in [Fig. 3], [Fig. 5] and [Fig. 7], axis of each of the pinion bevel gears is perpendicular to that of central steering shaft. Pinion bevel gears (CPB1), (CPB2), (CPB3) and (CPB4) are meshingly engaged with bottom bevel gear and top bevel gear.

[24] As shown in [Fig. 3], central tubular cage (CTC) consists of two C-shaped rods and four L-shaped rods, surrounding central gear set, with one C-shaped rod on the front side of central gear set with its upper and lower ends connected to upper section (CHT1) and lower section (CHT2), respectively, of central head tube; one C-shaped rod on the rear side of central gear set with its upper and lower ends connected to upper section (CHT1) and lower section (CHT2), respectively, of central head tube; one L-shaped on upper right side of central gear set with its ends connected to right steer arm of steer transmission mechanism and upper section (CHT1) of central head tube; one L-shaped rod lower right side of central gear set with its ends connected to right steer arm of steer transmission mechanism and lower section (CHT2) of central head tube; one L-shaped upper left side of central gear set with its ends connected to left steer arm of steer transmission mechanism and upper section (CHT1) of central head tube; and one L- shaped rod on lower left side of central gear set with its ends connected to left steer arm of steer transmission mechanism and lower section (CHT2) of central head tube.

[25] As shown in [Fig. 3], [Fig. 7] and [Fig. 10], pinion bevel gears on front and rear side (CPB1) and (CPB2) are coaxially connected at their outer side to horizontal rods extending from the central tubular cage via ball bearings (CBB1) and (CBB2) respectively. Central pinion bevel gears (CPB3) and (CPB4) are held in place by steer transmission mechanism (STM).

Left wheel steering system

[26] As shown in [Fig. 1] and [Fig. 3], left wheel steering system consists of a wheel (LW), left steering fork (LSF), left head tube (LHT), left gear set and left tubular cage (LTC).

[27] As shown in [Fig. 1] and [Fig. 3], left wheel steering fork (LSF) is a rigid/ suspension fork with steerer rod (LSR) with fork blades at their ends holding the wheel (LW) at the ends of its axle. Left head tube (LHT) is a set of two sections of vertical tubes, upper section (LHT1) and lower section (LHT2) separated by distance equal to the height of central gear set with each section coaxially holding the central steering shaft using ball bearings.

[28] As shown in [Fig. 3], [Fig. 7], and [Fig. 11], left gear set consists of two coaxially

parallel bevel gears (LBG1) and (LBG2) coaxially connected to left steering shaft, a pinion bevel gear (LPB1) on the front, a pinion bevel gear (LPB2) on the rear, a pinion bevel gear (LPB3) on the left and a pinion bevel gear (LPB4) on the right side of the left wheel steerer rod with each pinion bevel gear having axis perpendicular to the axis of steering shaft. As shown in [Fig. 1], [Fig. 3] and [Fig. 5], bottom bevel gear (LBG2) is fixedly connected to the left wheel steerer rod (LSR) and top bevel gear (LBG1) is coaxially mounted on left wheel steerer rod (LSR) via ball bearing so that it is free to rotate. As shown in [Fig. 3], [Fig. 5], and [Fig. 11], axis of each of the pinion bevel gears is perpendicular to that of left steerer rod (LSR). Each of pinion bevel gears (LPB1) (LPB2) (LPB3) and (LPB4) is engaged with top and bottom bevel gear.

[29] As shown in [Fig. 1] and [Fig. 3], left tubular cage (LTC) consists of three C-shaped rods and two L-shaped rods, surrounding left wheel gear set, with one C-shaped rod on the front side of central gear set with its upper and lower ends connected to upper section (LHT1) and lower section (LHT2), respectively, of left wheel head tube; one C-shaped rod on the rear side of left wheel gear set with its upper and lower ends connected to upper section (LHT1) and lower section (LHT2), respectively, of left wheel head tube; one C-shaped rod on the left side of left wheel gear set with its upper and lower ends connected to upper section (LHT1) and lower section (LHT2), respectively, of left wheel head tube; one L-shaped on upper right side of left wheel gear set with its ends connected to right steer arm of steer transmission mechanism and upper section (LHT1) of left wheel head tube; one L-shaped rod lower right side of left wheel gear set with its ends connected to right steer arm of steer transmission mechanism and lower section (LHT2) of left wheel head tube.

[30] As shown in [Fig. 3], [Fig. 7] and [Fig. 10], left pinion bevel gears on front, rear side and left side (LPB1), (LPB2) and (LPB3), are coaxially connected at their outer side to horizontal rods extending from the central tubular cage via ball bearings (LBB1),

(LBB2) and (LBB3) respectively. Left pinion bevel gears (LPB2) and (LPB4) are held in place by steer transmission mechanism (STM).

Right wheel steering system

[31] As shown in [Fig. 1] and [Fig. 3], right wheel steering system (RSS) consists of a wheel (RW), left steering fork (RSF), left head tube (RHT), right gear set (RGS) and right tubular cage (RTC).

[32] As shown in [Fig. 1] and [Fig. 3], right steering fork (RSF) is a rigid/ suspension fork with steerer rod (RSR) with fork blades at their ends holding the wheel (RW) at the ends of its axle.

[33] As shown in [Fig. 1] and [Fig. 3], right head tube (RHT) is a set of two sections of

vertical tubes, upper section (RHT1) and lower section (RHT2) separated by distance equal to the height of right gear set with each section coaxially holding the central steering shaft using ball bearings. [34] As shown in [Fig. 3], [Fig. 7] and [Fig. 10], right gear set (RGS) consists of two coaxially parallel bevel gears (RBG1) and (RBG2) coaxially connected to right steering shaft, a pinion bevel gear (RPB1) on the front, a pinion bevel gear (RPB2) on the rear, a pinion bevel gear (RPB3) on the left and a pinion bevel gear (RPB4) on the right side of the right wheel steerer rod with each pinion bevel gear having axis perpendicular to the axis of steering shaft.

As shown in [Fig. 3] and [Fig. 5], bottom bevel gear (RBG2) is fixedly connected to the right wheel steerer rod (RSR) and top bevel gear (RBG1) is coaxially mounted on right wheel steerer rod (RSR) via ball bearing so that it is free to rotate.

As shown in [Fig. 3], [Fig. 7] and [Fig. 10], axis of each of the pinion bevel gears is perpendicular to that of right steerer rod (RSR). Each of pinion bevel gears (RPB1) (RPB2) (RPB3) and (RPB4) is engaged with top and bottom bevel gear.

[35] Right tubular cage (RTC) consists of three C-shaped rods and two L-shaped rods,

surrounding right wheel gear set, with one C-shaped rod on the front side of central gear set with its upper and lower ends connected to upper section (RHT1) and lower section (RHT2), respectively, of right wheel head tube; one C-shaped rod on the rear side of right wheel gear set with its upper and lower ends connected to upper section (RHT1) and lower section (RHT2), respectively, of right wheel head tube; one C-shaped rod on the right side of right wheel gear set with its upper and lower ends connected to upper section (RHT1) and lower section (RHT2), respectively, of right wheel head tube; one L- shaped on upper right side of right wheel gear set with its ends connected to right steer arm of steer transmission mechanism and upper section (RHT1) of right wheel head tube; one L-shaped rod lower right side of right wheel gear set with its ends connected to right steer arm of steer transmission mechanism and lower section (RHT2) of right wheel head tube.

[36] As shown in [Fig. 3], [Fig. 7] and [Fig. 10], right pinion bevel gears on front, rear side and right side (RPB1), (RPB2) and (RPB4) are coaxially connected at their outer side to horizontal rods extending from the central tubular cage via ball bearings (RBB1),

(RBB2) and (RBB3) respectively. Right pinion bevel gears (RPB3) are held in place by steer transmission mechanism (STM).

Steer Transmission Mechanism [37] Central steering system is coupled with left wheel steering system and right wheel steering system via steer transmission mechanism (STM). Steer transmission mechanism (STM) consists of two transverse straight shafts, one (TS1) on right side coaxially connecting bevel pinion gears (CPB3) and (LPB4), and one (TS2) on left side coaxially connecting bevel pinion gears (CPB4) and (RPB3), of the central gear set with transverse shaft (TS1) and (TS2) coaxially encased in head tube arms (TH1) and (TH2) respectively via ball bearings. Head tube arms on the left side and right side are connected at their rear side to top tube via rods left top tube arm (LTTA) and right top tube arm (RTTA) respectively.

Steer Operation

[38] On rotation in clockwise direction, handle causes bevel gear (CBG1) to rotate clockwise direction which in turn causes all the central pinion gears to rotate with the central pinion bevel gears (CPB3) rotating in direction opposite to that of (CPB4). Rotation of (CPB3) causes to rotate left wheel pinion gears (LPB4) respectively via transmission shafts which in turn causes left wheel bottom bevel gear (LBG2) to rotate in clockwise direction and thus steer left wheel in clockwise direction. Similarly rotation of (CPB4) causes to rotate right wheel pinion gears (RPB3) respectively via transmission shafts which in turn causes right wheel bottom bevel gear (RBG2) to rotate in clockwise direction and thus steer right wheel in clockwise direction. Central pinion gears (CPB1) and (CPB2) and central bottom bevel gear (CBG2) are auxiliary gears which help to couple the steering action of upper bevel gear (CBG1) between upper and lower side of pinion bevel gears (CPB2) and (CPB4). Left wheel pinion gears (LPB1), (LPB2) and (LPB3), and left upper bevel gears (LBG1) are auxiliary gears which help to couple the steering action of left wheel pinion bevel gears (LPB4). Similarly right wheel pinion gears (RPB1), (RPB2) and (RPB3), and left upper bevel gears (RBG1) are auxiliary gears which help to couple the steering action of left wheel pinion bevel gears (RPB4).

[39] Bevel-pinion gear set used in central, left and right gear set can have various variations.

According to one variation , as shown in [Fig. 13] and [Fig. 14], in central gear set front and rear gears are bevel gears and top and bottom gears are pinion bevel gears. In this variation rider will have more leg space.