Transmission for wheeled machine

Patent metadata

Field	Value
Publication number	US-10550899-B2
Application number	US-201815941190-A
Country	US
Kind code	B2
Filing date	Mar 30, 2018
Priority date	Mar 30, 2018
Publication date	Feb 4, 2020
Grant date	Feb 4, 2020

Abstract

A transmission for a manually operated wheeled machine includes an output shaft having a close-ended axial channel. A drive gear mounted on the output shaft includes an engaging groove. A ratchet is received in the channel and is in engagement with the engaging groove. A holder mounted on the output shaft includes a relief that receives the ratchet. A friction member applies radial friction to the holder to temporarily prevent rotation of the holder with the output shaft in a drive condition of the machine moving the ratchet into engagement with the engaging groove, and in the drive condition the drive gear and holder rotate with the output shaft. In a freewheeling condition of the machine the output shaft is stationary, and an overdrive of the drive gear disengages the ratchet from the engaging groove allowing for free rotation of the drive gear about the stationary output shaft.

First claim

The invention claimed is:

1. A transmission for a manually operated wheeled machine having a drive condition and a freewheeling condition, the transmission comprising:
an output shaft having a close-ended channel formed in an end portion thereof, the channel extends in an axially longitudinal direction of the output shaft and is axially spaced from an end face of the output shaft;
a drive gear rotatably mounted on the end portion of the output shaft, the drive gear includes an engaging groove formed in an inner peripheral surface of the drive gear, the drive gear is meshingly engaged with a driven gear carried within a drive wheel of the wheeled machine;
a ratchet having a key portion and a leg portion extending from the key portion in a radial direction of the output shaft, the key portion is received in the channel and is in selective engagement with the engaging groove;
a holder rotatably mounted on the end portion of the output shaft, the holder includes an end face confronting the drive gear, a relief formed in the end face receives the leg portion of the ratchet; and
a friction member secured to the holder and adapted to apply radial friction to the holder to temporarily prevent rotation of the holder with the output shaft in the drive condition of the wheeled machine, and, as a result, the key portion of the ratchet is moved into engagement with the engaging groove of the drive gear, where in the drive condition the output shaft rotates in a first rotational direction together with the drive gear and the holder,
where in the freewheeling condition the output shaft is stationary, an overdrive of the drive gear in the first rotational direction results in disengagement of the key portion of the ratchet with the engaging groove allowing for free rotation of the drive gear about the stationary output shaft.

2. The transmission of claim 1 , wherein to prevent dust intrusion into the channel the drive gear and the holder are arranged on the end portion of the output shaft to cover the channel in both the drive condition and the freewheeling condition of the wheeled machine.

3. The transmission of claim 2 , wherein an inside wheel cover of the drive wheel includes a shroud covering each of the drive gear and the holder.

4. The transmission of claim 1 , wherein the friction member is a spring member at least partially wrapped about an outer peripheral surface of the holder.

5. The transmission of claim 4 , wherein a free end portion of the spring member is secured to an inside wheel cover of the drive wheel.

6. The transmission of claim 4 , wherein the outer peripheral surface of the holder includes a circumferential recess sized to receive the spring member.

7. The transmission of claim 1 , wherein the channel is rectangular in cross-section taken perpendicular to the axially longitudinal direction of the output shaft, the channel defined by first and second sides and a base, and
wherein the key portion of the ratchet includes a first end having first inclined surfaces and a second end, where in the drive condition the first inclined surfaces engage the first side and the base of the channel, and the second end engages the engaging groove of the drive gear.

8. The transmission of claim 7 , wherein the second end of the ratchet includes a curved surface allowing the second end to slide along the second side of the channel as the wheeled machine transitions from the drive condition to the freewheeling condition.

9. The transmission of claim 7 , wherein the second end includes a second inclined surface, where in the freewheeling condition the second inclined surface engages the inner peripheral surface of the drive gear.

10. The transmission of claim 1 , wherein the relief of the holder is defined by a forward surface and a rear surface relative to the first rotational direction of the output shaft, where in the drive condition the leg portion of the ratchet contacts the forward surface and is spaced from the rear surface.

11. The transmission of claim 10 , wherein a forward surface of the leg portion of the ratchet includes a first section and a second section canted relative to the first section, where in the drive condition the first section is in contact with the forward surface, as the wheeled machine transitions from the drive condition to the freewheeling condition the leg portion pivots on the forward surface, and where in the freewheeling condition the second section is in contact with the forward surface.

12. The transmission of claim 1 , wherein the inner peripheral surface of the drive gear is polygonal shaped.

13. A manually operated wheeled machine having a drive condition and a freewheeling condition, the wheeled machine comprising:
a motor;
an output shaft operably coupled to the motor, the output shaft has a close-ended channel formed in an end portion thereof, the channel extends in an axially longitudinal direction of the output shaft and is axially spaced from an end face of the output shaft;
a drive wheel connected to the end portion of the output shaft, the drive wheel including an inside wheel cover having an opening for the output shaft; and
a transmission housed within the drive wheel, wherein the transmission includes:
a drive gear rotatably mounted on the end portion of the output shaft, the drive gear includes an engaging groove formed in an inner peripheral surface of the drive gear,
a ratchet having a key portion and a leg portion, the key portion is received in the channel, the ratchet is in selective engagement with the engaging groove,
a holder rotatably mounted on the end portion of the output shaft immediately adjacent the drive gear, the holder includes an end face having a relief formed therein which receives the leg portion of the ratchet,
a driven gear carried within the drive wheel and meshingly engaged with the drive gear,
wherein to prevent dust intrusion into the channel the drive gear and the holder are arranged on the end portion of the output shaft to cover the channel, and the inside wheel cover includes a shroud covering each of the drive gear and the holder.

14. The wheeled machine of claim 13 , wherein a friction member is secured to the holder and adapted to apply radial friction to the holder to temporarily prevent rotation of the holder with the output shaft in the drive condition of the wheeled machine.

15. The wheeled machine of claim 14 , where in the drive condition the key portion of the ratchet engages the engaging groove of the drive gear, and the output shaft rotates in a first rotational direction together with the drive gear and the holder, and
where in the freewheeling condition the output shaft is stationary, an overdrive of the drive gear in the first rotational direction results in disengagement of the key portion of the ratchet with the engaging groove allowing for free rotation of the drive gear about the stationary output shaft.

16. The wheeled machine of claim 14 , wherein the friction member is at least partially wrapped about an outer peripheral surface of the holder, and a free end portion of the friction member is secured to the inside wheel cover of the drive wheel.

17. The wheeled machine of claim 13 , wherein the channel is rectangular in cross-section taken perpendicular to the axially longitudinal direction of the output shaft.

18. A transmission for a manually operated wheeled machine having a drive condition and a freewheeling condition, the transmission comprising:
an output shaft having a close-ended channel formed in an end portion thereof, the channel extends in an

Assignees

• Honda Motor Co Ltd

Inventors

• Vaughn Christopher W
• Lenfert Nathaniel

Classifications

• F16D2041/0603

  Sprag details · CPC title

• F16D41/14

  the effective stroke of the pawl being adjustable · CPC title

• A01D34/69 Primary

  with motor driven wheels · CPC title

• A01D2034/6837

  Drive connections · CPC title

• F16D2041/0608

  Races with a regular polygon shape · CPC title