Compact drive mechanism with selective reverse power output

A drive mechanism effects a rotary power output in a selected one of opposite first and second power output directions in response to a reciprocating power input resulting from substantially linear forces applied to the drive mechanism. The drive mechanism includes input bevel gears meshed with corresponding output bevel gears coupled to a common power output shaft through clutches that effect a rotary power output at the power output shaft in response to the reciprocating power input from the substantially linear forces. Opposite crank arms are coupled with the input bevel gears such that each crank arm is advanced by an applied substantially linear force, and is retracted upon advancement of the opposite crank arm. A selector enables selection of either one of the opposite directions of rotation of the power output shaft, without requiring a change in the manner in which the linear force input is applied.

The present invention relates generally to drive mechanisms and pertains, more specifically, to a compact gear drive mechanism for effecting a rotary power output in response to a reciprocating input, such as substantially linear arm or leg movements of an operator and, more particularly, to such a compact drive mechanism in which the direction of the rotary power output is selectively reversible.

In a preferred embodiment, the drive mechanism of the present invention enables a human operator to apply input power using reciprocating substantially linear arm motion or leg motion to create an effective rotary power output, and selectively to effect reversals in the direction of rotation of the rotary power output, without changing the manner in which the reciprocating input is applied. A myriad of devices, equipment and apparatus which require a rotary power input are improved by the incorporation of the present drive mechanism to allow a human operator to use arms or legs moved along substantially linear paths to apply, with greater ease, comfort and effectiveness, forces to be converted by the drive mechanism into a rotational output well suited to the provision of a requisite rotary power output.

Examples of such devices, equipment and apparatus are as follows: Wheeled vehicles such as bicycles, tricycles and carts in which substantially linear leg movements of an operator are used to create a rotational output for driving at least one drive wheel of the vehicle; boat propulsion systems in which substantially linear arm or leg movements of an operator create a rotational power output to at least one propeller of the propulsion system; exercise equipment and machines in which substantially linear arm or leg movements drive at least one rotating resistance member; lifts, hoists, winches and windlasses in which a power input from substantially linear arm movements provide rotational power for rotating a drum or pulley system. In addition, the present gear drive mechanism is adapted readily to a very wide variety of industrial uses where substantially linear movements of a worker's arms or legs can be converted effectively to provide a rotary power output. The present invention enables selection of the direction of rotation of the rotary power output, without requiring a change in the manner in which the essentially linear input is applied.

A compact drive mechanism constructed in accordance with the present invention provides a unique drive system in which reciprocating cranks are coupled to a driven output shaft through a drive system that incorporates all of the recognized advantages of reciprocating crank arrangements while attaining highly desirable additional objects and advantages not heretofore made available in a drive system. Among these objects and advantages are: Increased effectiveness and greater simplicity of construction in a drive mechanism that converts reciprocating substantially linear input forces to a rotary power output having a direction of rotation that is selectively reversed without requiring a change in the manner in which the essentially linear input forces are applied; provides a compact construction for increased versatility and widespread use in a myriad of applications; reduces any possible loss of effectiveness while converting reciprocating substantially linear input forces into a continuous rotary power output selectively directed in either one of opposite directions of rotation; provides increased ease of operation and higher efficiency through a more uniform application of a driving force by an operator of the mechanism; enables ready adjustment for different performance objectives; exhibits smooth and quiet operation; reduces wear of component parts of a drive system; provides more resistance to dust, debris and other foreign matter encountered in the field; reduces requirements for periodic maintenance and repair; enables increased longevity for exemplary performance over an extended service life.

The above objects and advantages, as well as further objects and advantages, are attained by the present invention, which may be described briefly as a drive mechanism for effecting a rotary power output in a selected one of opposite first and second power output directions in response to a reciprocating power input resulting from essentially same-directed substantially linear forces applied to the drive mechanism, the drive mechanism comprising: a first input drive arrangement mounted for rotation in each one of opposite first and second input directions of rotation about a first input axis of rotation, the first input drive arrangement being rotatable in the first input direction of rotation in response to a first substantially linear force applied to the first input drive arrangement; a second input drive arrangement mounted for rotation in each one of opposite first and second input directions of rotation about a second input axis of rotation, the second input drive arrangement being rotatable in the first input direction of rotation in response to a second substantially linear force applied to the second input drive arrangement; a first output drive arrangement mounted for rotation about a first output axis of rotation, the first output drive arrangement being coupled with the first input drive arrangement for rotation of the first output drive arrangement in a first output direction of rotation in response to rotation of the first input drive arrangement in the first input direction of rotation, and being coupled with the second input drive arrangement for rotation of the first output drive arrangement about the first output axis of rotation in a second output direction of rotation, opposite to the first output direction of rotation, in response rotation of the second input drive arrangement in the first input direction of rotation; a second output drive arrangement mounted for rotation about a second output axis of rotation, the second output drive arrangement being coupled with the second input drive arrangement for rotation of the second output drive arrangement about the second output axis of rotation in the first output direction of rotation in response to rotation of the second input drive arrangement in the first input direction of rotation, and being coupled with the first input drive arrangement for rotation of the second output drive arrangement about the second output axis of rotation in the second output direction of rotation, opposite to the first output direction of rotation, in response to rotation of the first input drive arrangement in the first input direction of rotation; a power output shaft mounted for rotation in either one of the first and second power output directions about a power output axis of rotation; a clutch arrangement for actuation between a first condition wherein the first output drive arrangement is coupled with the power output shaft for effecting rotation of the power output shaft in the first power output direction in response to rotation of the first input drive arrangement in the first input direction of rotation, while enabling rotation of the first input drive arrangement in the second input direction of rotation independent of rotation of the power output shaft, and the second output drive arrangement is coupled with the power output shaft for effecting rotation of the power output shaft in the first power output direction in response to rotation of the second input drive arrangement in the first direction of rotation, while enabling rotation of the second input drive arrangement in the second input direction of rotation independent of rotation of the power output shaft, and a second condition wherein the second output drive arrangement is coupled with the power output shaft for effecting rotation of the power output shaft in the second power output direction in response to rotation of the first input drive arrangement in the first input direction of rotation, while enabling rotation of the first input drive arrangement in the second input direction of rotation independent of rotation of the power output shaft, and the first output drive arrangement is coupled with the power output shaft for effecting rotation of the power output shaft in the second power output direction in response to rotation of the second input drive arrangement in the first input direction of rotation, while enabling rotation of the second input drive arrangement in the second input direction of rotation independent of rotation of the power output shaft; and a selector mechanism coupled with the clutch arrangement for actuating the clutch arrangement selectively into one of the first and second conditions; whereby the first and second substantially linear forces applied to the drive mechanism in the same manner enable a rotary power output in either selected one of the first and second power output directions at the power output shaft.

Referring now to the drawing, and especially toFIG. 1thereof, a compact drive mechanism constructed in accordance with the present invention is shown at10and carries opposite crank arms in the form of a left crank arm12and a right crank arm14, both crank arms12and14being mounted for rotation about a common axis of rotation IR.

Turning now toFIGS. 2 through 6, as well as with reference toFIG. 1, drive mechanism10includes a casing in the form of a gear box22which seals the interior24of the gear box22against the entry of foreign matter encountered outside the gear box22while maintaining a gear train30within the interior24, in working arrangement and protected against outside elements. Gear train30is comprised of four bevel gears, including a left-input drive gear32of a first input drive arrangement, a right-input drive gear34of a second input drive arrangement, a forward drive gear36of a first output drive arrangement, and a rearward drive gear38of a second output drive arrangement, all of which gears are meshed in an orthogonal, box-like arrangement, as seen inFIG. 5. The left-input drive gear32is connected to the left crank arm12through a left collar42, secured to both the left crank arm12and the left-input drive gear32, and the right-input drive gear34is connected to the right crank arm14through a right collar44secured to both the right crank arm14and the right-input drive gear34. The drive gears32and34are journaled for rotation on respective stationary stub shafts46and48for rotation about the common input axis of rotation IR, while both drive gears36and38are journaled for rotation about a common output axis of rotation OR.

The forward drive gear36and the rearward drive gear38are coupled with a power output shaft50, as follows: As seen inFIGS. 5 and 6, an external splined section52extends along external surface54of power output shaft50and is engaged with a complementary internal splined section56extending along internal surface58of a coupler in the form of a sleeve60in sliding engagement coaxial with power output shaft50, along the engaged splined sections52and56. The engaged splined sections52and56also couple the power output shaft50for rotation with the sleeve60, while enabling sliding movement of the sleeve60along the power output shaft50and axis OR, as will be described below.

A clutch arrangement includes a first clutch set having a first one-way clutch70affixed to the rearward drive gear38and coupling the rearward drive gear38with sleeve60by means of an internal splined section72on clutch70, shown inFIGS. 5 and 6engaged with an external splined section74extending along an outer surface portion76of sleeve60. A second one-way clutch80is affixed to the forward drive gear36and couples the forward drive gear36with sleeve60by means of an internal splined section82on clutch80, shown engaged with an external splined section84extending along an outer surface portion86of sleeve60. Thus, in the illustrated compact orthogonal arrangement, the input axis of rotation IR is substantially perpendicular to output axis of rotation OR, and the output axis of rotation OR is coextensive with a power output axis of rotation WR.

Upon the application of a substantially linear force FL to left crank arm12, movement of the left crank arm12will rotate left-input drive gear32in the direction of arrow90which, in turn, will rotate the rearward drive gear38in the direction of arrow92. Clutch70is arranged to couple rearward drive gear38with power output shaft50, through the splined engagements between splined sections72and74, and between splined sections52and54, so that upon rotation of rearward drive gear38in the direction of arrow92, power will be transmitted from the left-input drive gear32to the rearward drive gear38, and then, through sleeve60, to power output shaft50which also is rotated in the direction of arrow92, as the left crank arm12is moved by force FL from a retracted position, shown in full lines, to an advanced position, depicted in a superposed phantom image at100, inFIG. 3.

At the same time, the forward drive gear36will be rotated by the left-input gear32in the direction of arrow110, clutch80being arranged to uncouple forward drive gear36from sleeve60and thereby allow free rotation of forward drive gear36relative to and independent of sleeve60and power output shaft50, in the direction of arrow110. Rotation of rearward drive gear38in the direction of arrow92, and rotation of forward drive gear36in the direction of arrow110, will effect rotation of right-input drive gear34in the direction of arrow112, consequently rotating right crank arm14to retract the right crank arm14from the advanced position, shown in full lines, to a retracted position depicted in a superposed phantom image at120, inFIG. 3.

With the right crank arm14now at the retracted position120, and the left crank arm12at the advanced position100, an operator (not shown) can apply a substantially linear force FR to the right crank arm14, to move the right crank arm14toward the advanced position and rotate the right-input drive gear34in the direction of arrow122. In turn, the forward drive gear36will be rotated in the direction of arrow124. Clutch80is arranged to couple forward drive gear36with sleeve60upon rotation of forward drive gear36in the direction of arrow124, so that power is transmitted from the right-input drive gear34to the forward drive gear36, and then, through sleeve60, to power output shaft50which also is rotated in the direction of arrow124, which is the same direction as indicated by arrow92, as the right crank arm14is moved from the retracted position120toward an advanced position.

At the same time, the rearward drive gear38will be rotated by the right-input drive gear34in the direction of arrow126, clutch70being arranged to uncouple rearward drive gear38from sleeve60and thereby allow free rotation of rearward drive gear38relative to and independent of sleeve60and power output shaft50, in the direction of arrow126. Rotation of forward drive gear36in the direction of arrow124, and rotation of rearward drive gear38in the direction of arrow126, will effect rotation of left-input drive gear32in the direction of arrow128, consequently rotating left crank arm12to retract the left crank arm12from the advanced position100toward the retracted position, thereby completing a full cycle of operation in which power output shaft50is rotated about power output axis of rotation WR in the direction of arrow92.

With reference now toFIGS. 7 through 9, when desired, the direction of rotation of power output shaft50can be reversed, selectively, without requiring a change in the manner in which the essentially linear forces FL and FR are applied to the drive mechanism10. To that end, a selector mechanism130is coupled with the clutch arrangement and is seen to include an actuator in the form of a selector dial132mounted for rotation within gear box22about an axis SA extending orthogonal to axes IR and OR and accessible, for selective rotation, at the top of gear box22where a finger grip134is provided for facilitating the selective rotation of dial132between the position illustrate inFIG. 1and the position shown inFIG. 9. A drive pin136is carried by dial132and projects into a yoke140which is mounted for linear sliding movement substantially parallel to axis OR, within diametrically opposed slots, one of which slots is illustrated at142, between a first position, illustrated inFIG. 6, and a second position, shown inFIG. 7, in response to rotation of dial132through a displacement of 180° to index the selector mechanism130into one of the two orientations depicted inFIGS. 1 and 9, corresponding to one of the two positions of yoke140shown respectively inFIGS. 6 and 7. A driven pin144is carried by yoke140and engages a circumferential groove146in sleeve60such that upon rotation of dial132and concomitant linear movement of yoke140and drive pin136, driven pin144will move sleeve60between the position illustrated inFIG. 6and the position illustrated inFIG. 7. A detent150maintains the dial132in either one of the positions shown inFIGS. 1 and 9and, accordingly, the sleeve60, in either selected one of the two positions shown inFIGS. 6 and 7.

As described above, when the sleeve60is in the position illustrated inFIG. 6, the clutch arrangement is in a first condition wherein the clutches70and80of the first clutch set operate in concert to enable rotation of the power output shaft50in the direction of arrow92, in response to the substantially linear forces FL and FR applied, respectively, and alternately, to the left and right crank arms12and14. When the dial132is rotated through 180°, to the position shown inFIGS. 7 through 9, sleeve60is moved along power output shaft50to be placed in the position illustrated inFIGS. 7 and 8, thereby disengaging the splined sections74and84of sleeve60respectively from the splined sections72and82of clutches70and80. The clutch arrangement includes a second clutch set having a third one-way clutch170affixed to the rearward drive gear38and including a spline section172, and a fourth one-way clutch180affixed to the forward drive gear36and including a spline section182. Upon movement of the sleeve60into the position illustrated inFIGS. 7 and 8, the clutch arrangement is actuated into a second condition wherein splined sections74and84of sleeve60are engaged respectively with splined sections172and182of the third and fourth clutches170and180.

Now, upon the application of a substantially linear force FL to left crank arm12, movement of the left crank arm12will rotate left-input drive gear32in the direction of arrow90which, in turn, will rotate the forward drive gear38in the direction of arrow110. However, clutch180is arranged to couple forward drive gear36with power output shaft50, through the splined engagements between splined sections182and84, and between splined sections52and54, so that upon rotation of forward drive gear36in the direction of arrow110, power will be transmitted from the left-input drive gear32to the forward drive gear36, and then, through sleeve60, to power output shaft50which also is rotated in the direction of arrow110, as the left crank arm12is moved by force FL to the advanced position, depicted in phantom at100inFIG. 3. Thus, when the dial132is in the selected position shown inFIG. 9, rotation of the power output shaft50is in the direction of arrow110, opposite to the direction of rotation as depicted by arrow92.

At the same time, the rearward drive gear38will be rotated by the left-input drive gear32in the direction of arrow92, clutch170being arranged to uncouple rearward drive gear38from sleeve60and thereby allow free rotation of rearward drive gear38relative to and independent of sleeve60and power output shaft50, in the direction of arrow92. Rotation of forward drive gear36in the direction of arrow110, and rotation of rearward drive gear38in the direction of arrow92, will effect rotation of right-input drive gear34in the direction of arrow112, consequently rotating right crank arm14to retract the right crank arm14toward the retracted position, depicted in phantom at120inFIG. 3.

With the right crank arm14now at the retracted position120, and the left crank arm12at the advanced position100, an operator (not shown) can apply a substantially linear force FR to the right crank arm14to move the right crank arm14toward the advanced position and rotate the right-input drive gear34in the direction of arrow122. In turn, the rearward drive gear38will be rotated in the direction of arrow126. Clutch170is arranged to couple rearward drive gear38with sleeve60upon rotation of rearward drive gear38in the direction of arrow126, so that power will be transmitted from the right-input drive gear34to the rearward drive gear38, and then through sleeve60to power output shaft50which also will be rotated in the direction of arrow126, as the right crank arm14is moved from the retracted position120toward the advanced position shown in full lines inFIG. 3. At the same time, the forward drive gear36will be rotated by the right-input gear34in the direction of arrow110, clutch180being arranged to uncouple forward drive gear36from sleeve60and thereby allow free rotation of forward drive gear36relative to and independent of sleeve60and power output shaft50, in the direction of arrow124. Rotation of rearward drive gear38in the direction of arrow126, and rotation of forward drive gear36in the direction of arrow124, will effect rotation of left-input drive gear32in the direction of arrow128, consequently rotating left crank arm12to retract the left crank arm12from the advanced position100toward the retracted position shown in full lines inFIG. 3, thereby completing a full cycle of operation in which the power output shaft50is rotated about power output axis of rotation WR in the direction of arrow110, opposite to the aforesaid direction of rotation depicted by arrow92. Thus, merely by operating selector mechanism130, the clutch arrangement is actuated into either one of the first and second conditions described above, enabling selection of the direction of the rotary power output at power output shaft50without requiring a change in the manner in which the substantially linear forces FL and FR are applied to the drive mechanism10.

Drive system10is compact, easily adjusted to the particular requirements of an application, and is integrated readily into a wide variety of applications. Internal gearing for gear drive30may be selected from any one of variety of available conventional internal gearing drives, enabling increased versatility. The sealed gear box22resists infiltration of dust, debris or other foreign matter which could cause deleterious effects such as diminished performance and premature wear, while reducing the requirement for frequent periodic maintenance and repair. Moreover, operation is quiet and smooth.

It will be apparent that drive mechanism10has applications in many settings that require a drive arrangement in which a reciprocating power input is coupled to a rotating power output shaft. Depending upon the requirements of a particular setting, drive mechanism10can be provided with suitable operating members, such as pedals, handgrips or the like. Thus, as noted in the examples set forth above, drive mechanism10can find use in propulsion systems for vehicles, including multiple wheeled vehicles such as bicycles, tricycles and carts and propeller drives for boats. In addition, drive mechanism10can be adapted to exercise machines and equipment, lifts, hoists, winches, windlasses and like devices, as well as to a wide variety of industrial uses where substantially linear reciprocating movements of an operator's arms or legs are converted to rotational movement of a power output shaft.

It will be seen that the present invention attains all of the objects and advantages outlined above, namely: Increased effectiveness and greater simplicity of construction in a drive mechanism that converts reciprocating substantially linear input forces to a rotary power output having a direction of rotation that is selectively reversed without requiring a change in the manner in which the essentially linear input forces are applied; provides a compact construction for increased versatility and widespread use in a myriad of applications; reduces any possible loss of effectiveness while converting reciprocating substantially linear input forces into a continuous rotary power output selectively directed in either one of opposite directions of rotation; provides increased ease of operation and higher efficiency through a more uniform application of a driving force by an operator of the mechanism; enables ready adjustment for different performance objectives; exhibits smooth and quiet operation; reduces wear of component parts of a drive system; provides more resistance to dust, debris and other foreign matter encountered in the field; reduces requirements for periodic maintenance and repair; enables increased longevity for exemplary performance over an extended service life.

It is to be understood that the above detailed description of preferred embodiments of the invention is provided by way of example only. Various details of design and construction may be modified without departing from the true spirit and scope of the invention, as set forth in the appended claims.