GB1588854A - Capstans - Google Patents

Description

(54) IMPROVEMENTS IN OR RELATING TO CAPSTANS (71) We, KABUSHIKI KAISHA IKEDA SEISAKUSHO, a Japanese company of 3-3, Muramatsubara 1 chome, Shimizu-shi, Shizuoka-ken, Japan and SUGITA SANGYO KABUSHIKI KAISHA, a Japanese company of 20-3, Shinkawa 2 chome, Chuo-ku, Tokyo, Japan, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The invention relates to a mooring arrangement, and more particularly, to a capstan for use in drawing in a rope which leads a marine vessel to a berth when anchoring the vessel to a berth such as a quay or a pier.

A capstan is mounted on the deck of the vessel or berth for drawing in a rope extending between the vessel and the berth, by anchoring its one end and hauling in the other end. As illustrated in Figure 3, the rope is wrapped around the drum a few turns, and is manually hauled in while rotating the drum. The capstan may be mounted on a quick release hook unit, thereby forming a mooring arrangement. The hook unit anchors one end of the rope in a manner to be releasable from a remote location.

Conventional capstans are typically of two kinds. In one kind, the drum, reduction gearing and motor are disposed in a longitudinal sequence so that the axis of the drum aligns with that of the motor. Normally a rigid housing is provided which receives the reduction gearing and the motor, and the drum is rotatably mounted on the housing. In the other kind, the axis of the drum is disposed at an angle of 90" from the axis of the motor, with the reduction gearing disposed at the point of intersection of these axes, thus forming an L-shaped assembly.

In this instance, the reduction gearing includes a rigid housing and the motor is disposed alongside the housing while the drum is mounted on top of the housing.

With conventional capstans as described above, the drum is mounted on top of the drive unit and thus has an increased elevation, which disadvantageously affects the ease of operation. To avoid such difficulty, there has been proposed the provision of a pit in the deck or berth within which the drive unit is to be received. However, this approach involves an increased installation cost and requires some means which prevents the inundation of the pit. Also, the capstan cannot be mounted on top of a said hook unit with this arrangement. There is also known a capstan in which the drive unit is mounted on top of the drum in order to lower the level of the drum. How ever, this arrangement suffers from the disadvantage that the rope may be entangled with the drive unit when wrapping it around the drum.

According to the invention there is provided a capstan for use in hauling in a marine vessel by means of a rope, comprises ing, a base member, a drum rotatably mounted with respect to the base member and including a generally cylindrical body having a negative crown which is adapted to be engagingly encircled by a said rope, an electric motor including a housing which is rigidly mounted on the base member and disposed within the drum, the housing including a lower bracket, a substantially cylindrical sidewall and an upper bracket, the motor having a shaft which is coaxial with the drum and one end of which extends through the upper bracket, a cycloidal reduction gear disposed within the drum for drivingly connecting the drum with the motor, the reduction gear including an eccentric cam mounted on said end of the motor shaft, a planet gear mounted to slide around the cam, and an annular gear mounted inside the drum and meshing with the planet gear and having a number of teeth which is greater than that of the planet gear, the planet gear being formed with a plurality of circular openings disposed on a circle of a given radius from the centre of the planet gear, and support means for rotatably mounting the drum on the housing, the support means including a plurality of pins mounted on the upper bracket and disposed on a circle of a given radius from the axis of the shaft, each pin extending through a corresponding said cir cular opening, the support means also including a support bracket secured to the pins, and a bearing disposed between the support bracket and the drum.

In order that the invention may be readily understood an embodiment thereof will now be described by way of example and with reference to the accompanying drawings, in which: Figure 1 is a side elevation, partly in section, of a capstan in accordance with the invention; Figure 2 is a cross section taken along the line 2-2 shown in Figure 1; and Figure 3 is a perspective view of the capstan, illustrating its use.

Referring to Figure 1, the capstan comprises a drum 2 which is rotatably mounted on a base member 1. The drum 2 includes a somewhat cylindrical drum body 3 having a negative crown, i.e. having a reduced diameter at its intermediate portion than the diameter at its opposite ends, a top cover 4 and a bottom cover 5 which are firmly secured to the opposite ends of the drum body 3 by means of screws 6, 7. An electric motor 8 is disposed within the drum, and includes a housing 12 which comprises a lower bracket 9, a generally cylindrical side wall 10 and an upper bracket 11. By mount 'ing the lower bracket 9 on the base member 1, the motor is firmly mounted on the base member. Both upper and lower brackets 11, 9 carry bearings 13, 14, which rotatably support a shaft 16 carrying a rotor 15.The shaft 16 is aligned with the axis of the drum 2, and has its upper end 17 extending through the upper bracket 11. The generally cylindrical sidewall 10 carries a stator 18, and lead wires of the motor 8 are connected with connection box 19 disposed on the base member 1.

A cycloidal reduction gearing 20 is disposed within the drum 2 for operatively connecting the drum with the motor 8. In the example shown, the reduction gearing 20 comprises an annular gear 21 mounted on the inside of the drum 2, a pair of planet gears 22, 23 of an identical configuration and dimension and meshing with the annular gear. These planet gears are mounted around a pair of eccentric cams 24, 25 with bearings 36, 37 interposed therebetween. The eccentric cams are mounted on the end 17 of the motor shaft 16. The cams 24, 25 are of an identical profile, but are mounted on the shaft 16 with a phase displacement of 1800 from each other. For convenience of illustration, Figure 2 shows only one planet gear 22 and only one eccentric cam 24 in illustrating their relationship with the annular gear 21 and shaft 16.

Cycloidal reduction gearing is well known and therefore will not be described in detail.

However, the annular gear 21 generally has a number of teeth which is by one or two teeth greater than that of the planet gears 22, 23. The rotation of the shaft 16 causes a rotation of the eccentric cams 24, 25, which in turn causes a rotation of the planet gears 22, 23 simultaneously with a revolution thereof around the axis of the annular gear 21. The rotation of the planet gears causes the rotation of the annular gear 21. The use of two planet gears 22, 23 which are phase displaced from each other by 1800 stabilizes the rotation of the annular gear 21, but it should be understood that a single planet gear may be used if desired.

Each of the planet gears 22, 23 is formed with a plurality of circular openings 26 which are disposed on a circle of a given radius from the centre thereof. The openings 26 of both the planet gears partly register with each other when both the phase displaced gears are used in combination. The upper bracket 11 of the motor 8 carries a plurality of rigidly mounted pins 27 which extend through the registering portions of the circular openings 26 formed in the pair of planet gears 22, 23. These pins are disposed on a circle of a given radius from the axis of the motor shaft 16. Each pin 27 is provided with a rotatable sleeve 28 which is operatively engaged with the peripheral edge of the opening 26. The purpose of these sleeves is to minimize the abrasion of the teeth on the gears 21 to 23 since a slip between the planet gear and the annular gear is converted into a rolling movement.The upper ends of the pins 27 are rigidly connected to a common support bracket 30 by means of screws 29. The support bracket 30 carries a bearing 31 which rotatably supports the end 17 of the motor shaft 17 and also carries another bearing 32 which rotatably supports the drum 2.

The bearing 32 is disposed between a boss 33 of the support bracket 30 and a rib 34 formed on the top cover 4 of the drum 2.

At its lower end, the drum 2 is also rototably supported by a bearing 35 which is disposed between the bottom cover 5 and the lower bracket 9 of the motor 8.

Figure 3 shows the capstan in use. The base member 1 is directly mounted on the deck of a marine vessel or on the berth.

The base member may also be fixedly mounted on a hook unit, not shown, which is secured to the deck or berth. In either instance, the level of the drum 2 is lowered as compared with conventional capstans, thus facilitating the hauling operation by an 7 operator 40 who pulls the free end 42 of a rope 41 wrapped around the drum 2.

It will thus be seen that the capstan described is relatively simple in construction and easy to assemble, as well as being of a compact construction in which the motor and reduction gearing are assembled into the drum.

WHAT WE CLAIM IS: 1. A capstan for use in hauling in a marine vessel by means of a rope, comprises ing, a base member, a drum rotatably mounted with respect to the base member and including a generally cylindrical body having a negative crown which is adapted to be engagingly encircled by a said rope, an electric motor including a housing which is rigidly mounted on the base member and disposed within the drum, the housing including a lower bracket, a substantially cylindrical sidewall and an upper bracket, the motor having a shaft which is coaxial with the drum and one end of which extends through the upper bracket, a cycloidal reduction gear disposed within the drum for drivingly connecting the drum with the motor, the reduction gear including an eccentric cam mounted on said end of the motor shaft, a planet gear mounted to slide around the cam, and an annular gear mounted inside the drum and meshing with the planet gear and having a number of teeth which is greater than that of the planet gear, the planet gear being formed with a plurality of circular openings disposed on a circle of a given radius from the centre of the planet gear, and support means for rotatably mounting the drum on the housing, the support means including a plurality of pins mounted on the upper bracket and disposed on a circle of a given radius from the axis of the shaft, each pin extending through a corresponding said circular opening, the support means also including a support bracket secured to the pins, and a bearing disposed between the support bracket and the drum.

2. A capstan according to claim 1 in which the drum includes a top cover rigidly secured to the upper end of the drum body, said bearing being disposed between the top cover and the support bracket.

3. A capstan according to claim 1 or 2 in which the drum includes a bottom cover firmly secured to the lower end of the drum body, said support means including a second bearing disposed between the bottom cover and the lower bracket of the motor.

4. A capstan according to claim 1, 2, or 3 in which the reduction gear also includes a second eccentric cam mounted on said one end of the motor shaft and being of an identical profile as, but phase displaced from, the first mentioned eccentric cam, a second planet gear mounted to slide around the second eccentric cam and meshing with the inner gear, the second planet gear being of an identical configuration and dimension as, but phase displaced by 1800 from the first mentioned planet gear, said pins extending through registering openings of the both planet gears.

5. A capstan substantially as hereinbefore described with reference to the accompanying drawings. - -

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (5)

1. **WARNING** start of CLMS field may overlap end of DESC **.

   7 operator 40 who pulls the free end 42 of a rope 41 wrapped around the drum 2.

   It will thus be seen that the capstan described is relatively simple in construction and easy to assemble, as well as being of a compact construction in which the motor and reduction gearing are assembled into the drum.

   WHAT WE CLAIM IS: 1. A capstan for use in hauling in a marine vessel by means of a rope, comprises ing, a base member, a drum rotatably mounted with respect to the base member and including a generally cylindrical body having a negative crown which is adapted to be engagingly encircled by a said rope, an electric motor including a housing which is rigidly mounted on the base member and disposed within the drum, the housing including a lower bracket, a substantially cylindrical sidewall and an upper bracket, the motor having a shaft which is coaxial with the drum and one end of which extends through the upper bracket, a cycloidal reduction gear disposed within the drum for drivingly connecting the drum with the motor, the reduction gear including an eccentric cam mounted on said end of the motor shaft, a planet gear mounted to slide around the cam, and an annular gear mounted inside the drum and meshing with the planet gear and having a number of teeth which is greater than that of the planet gear, the planet gear being formed with a plurality of circular openings disposed on a circle of a given radius from the centre of the planet gear, and support means for rotatably mounting the drum on the housing, the support means including a plurality of pins mounted on the upper bracket and disposed on a circle of a given radius from the axis of the shaft, each pin extending through a corresponding said circular opening, the support means also including a support bracket secured to the pins, and a bearing disposed between the support bracket and the drum.
2. 2. A capstan according to claim 1 in which the drum includes a top cover rigidly secured to the upper end of the drum body, said bearing being disposed between the top cover and the support bracket.
3. 3. A capstan according to claim 1 or 2 in which the drum includes a bottom cover firmly secured to the lower end of the drum body, said support means including a second bearing disposed between the bottom cover and the lower bracket of the motor.
4. 4. A capstan according to claim 1, 2, or 3 in which the reduction gear also includes a second eccentric cam mounted on said one end of the motor shaft and being of an identical profile as, but phase displaced from, the first mentioned eccentric cam, a second planet gear mounted to slide around the second eccentric cam and meshing with the inner gear, the second planet gear being of an identical configuration and dimension as, but phase displaced by 1800 from the first mentioned planet gear, said pins extending through registering openings of the both planet gears.
5. 5. A capstan substantially as hereinbefore described with reference to the accompanying drawings. - -