GB1593971A - Power operated hinge assembly - Google Patents

Description

(54) A POWER OPERATED HINGE ASSEMBLY (71) We, TAYLOR HITEC LIMITED, a British Company of 77 Lyons Lane, Chorley, Lancashire, do hereby declare the invention, for which we pray that a Patent may be granted to us, and the method bv which it is to be performed to be particularly described in and by the following statement: The present invention relates to a power operated hinge for an articulated arm.

Articulated arms in which the articulated sections are pivotally connected by means of a power hinge, i.e. one which will effect relative movement of the arm sections, are known. It is a requirement of such hinges that they should allow a large degree of pivotal movement of the arms with respect to each other and generate a uniform and sufficient torque throughout this pivotal movement.

It is an object of the invention to provide such a hinge.

According to the present invention there is provided a power operated hinge assembly comprising a first cylindrical hinge element, a second hinge element relatively rotatable about the axis of said first hinge element, a motor, a first primary reduction gear for reducing the output speed of the motor, said first primary reduction gear having an output which is eccentric with respect to the axis of the first hinge element, a hypocycloidal gear formed of a tooth ring around the inside of the cylindrical hinge element and a pinion engaging said tooth ring and rotatably mounted about said eccentric output whereby rotation of said eccentric output nudges the pinion around the tooth ring, and means for transmitting the motion of said pinion to the second hinge element to effect said rotation of the second hinge element about the axis of the first hinge element.

In order to produce a smooth rotational movement of the second hinge element from the eccentric output motion of the pinion the coupling means is preferably a constant velocity joint, most preferably an Oldham Coupling.

Preferably the primary reduction gear is an epicyclic gear, most preferably a compound epicyclic gear.

The motor may, for example, be a hydraulic motor, although other types of motor, e.g. an electric motor, may be used depending on the environment in which the hinge will be used.

The motor used will be a reversible motor so as to allow the sections of the articulated arm to pivot in either direction.

The invention will be further described by way of example with reference to the accompanying drawing, which is a section view of a portion of an articulated arm incorporating one embodiment of hinge according to the invention.

Referring to the drawing, a hinge comprises a generally cylindrical casing 1 (constituting the first hinge element), second hinge elements 2 and 3 rotatably mounted one at each end of the casing 1, and a reversible hydraulic motor 4 for effecting relative movement of the hinge elements 2, 3 with respect to the casing I via an intermediate gearing system to be described more fully later.

Each hinge element 2 and 3 is generally circular and has a respective circular flange 2a and 3a, of greater diameter than the casing 1, which is a rotatable fit over a respective non-metallic bearing ring 2b or 3b (which may be replaced by other types of bearings) provided around the peripheral surface at the end of ring 1.

Between the rings 2b and 3b, one side of the casing I is connected to one section 5 of the articulated arm and this section serves also as a guiding support for rotation of the hinge elements 2 and 3. The other side of the arm has arcuate flanges 6 which serve the same purpose.

Each hinge element 2 and 3 has an integral extension plate 7 and 8 respectively and these plates are connected to a section 9 of the articulated arm. The sections 5 and 9 of the arm are thus pivotal with respect to each other.

The aforementioned hydraulic motor 4 which effects movement of the hinge elements 2 and 3 relative to the casing 1 is provided in a housing 10 which is mounted on the outside an end plate 11 itself locating within a central aperture of the hinge element 2. This motor 4 is of the type which comprises a rotary disc 12 and a ring 13 having a cam surface 14. The disc 12 has a plurality of cylinders 15 each of which accommodates a ball 16 engaging the cam surface 14, so that by appropriately supplying and exhausting hydraulic fluid to and from the cylinders 15 the disc is caused to rotate.

The motor 4 is drivingly connected to a shaft 17 which is supported in bearings 18.

The logitudinal axis of the shaft 17 coincides with that of the casing 1 and the shaft 17 has a terminal pinion 19.

The gear mechanism by means of which the drive of the motor 4 is transmitted to effect movement of the hinge elements 2, 3 with respect to the casing 1 will now be described.

Around a central portion of the inner surface of the casing 1 there is fixed a ring 20 in which are provided two sets of gear teeth. One set 21 is for use in a hypocycloidal reduction gear and is provided around the inner surface of the ring 20. The remaining set 22 is for use in a compound epicyclic reduction gear and is cut on the inner peripheral surface of an inwardly directed annular flange 23 of the ring 20.

At each side of the pinion 19 is a compound gear wheel 24 each of which comprises a gear wheel 25 and a smaller, integral, pinion 26.

Each wheel 25 is engaged by the pinion 19 and the centres of the pinion 19 and the two gear wheels 25 lie on a straight line. Each of the pinions 26 engage the teeth 22 cut in the ring 20.

For the purpose of support of the compound gear wheels 24, the gear wheels 25 and pinions 26 are provided with integral stub shafts 25a and 26a respectively. Each of the stub shafts 25a and 26a locate in a bush provided in a respective aperture of a collar 27 which rotatably supports the bearings 18 and is supported by bearings 28 such as a deep groove ball race, as shown, or a roller bearing. The stub shafts 26a each locate in a bush provided in an aperture of a terminal radial flange on a shaft 29, the other end of which is rotatably supported in a bearing 30 itself supported in an aperture in the hinge element 3.

As will be seen from the drawing, the shaft 29 has an eccentric portion 29a and this portion locates a roller bearing 31.

Around the roller bearing 31 is a pinion 32 which is of lesser diameter than, and which engages with the teeth ring 21 so as to form a hypocycloidal gear. The number of teeth on the pinion 32 and the teeth ring 21 are chosen depending on the degree of reduction which the hypocycloidal gear is desired to achieve.

If desired, an annular channel may be cut from a face of the pinion 32 for the purpose of weight reduction. The channel may if required be protected by a cover plate.

Machined on an end face of the pinion 32 is a set of aligned dogs 33 and similar dogs 34 are provided on the hinge element 3. A floating disc 35 with diametral slots at right angles to each other on opposed faces locates between the pinion 32 and hinge element 3 with the dogs 33 locating in one of said slots and the dogs 34 locating in the slots on the opposite face of the disc 35. This arrangement thus constitutes an "Oldham Coupling".

To complete the hinge unit, control means (not shown) will be provided for the motor 4 so that it may be operated from a control unit, e.g. in the cab of a vehicle which is provided with the articulated arm.

Furthermore, it will be appreciated that if the hinge is intended for underwater use, e.g. in an articulated arm of a submarine, the hinge will be made watertight and at least certain components will be produced of corrosion resistant material.

The operation of the hinge unit will now be described.

To effect pivotal movement of the arm sections 5 and 9, the controls (not shown) for the hinge are operated to start the motor 4 which thus drives the shaft 17. The compound gear wheels 24 are thus rotated by virtue of the engagement of the pinion 19 with the gear wheels 25, which rotate at a lower speed than the pinion 19 by virtue of the size difference.

Since the pinions 26 are integral with the gear wheels 25, they too rotate and must run around the tooth ring 22 because of their engagement therewith. The net effect is that the two compound gear wheels 24 follow each other around a circular path, at a rotational speed lower than that of pinion 26, and impart this rotational speed to the shaft 29.

The eccentric portion 29a of the shaft 29 rotates within bearing 31 and nudges the pinion 32 around the tooth ring 21 thus operating the hypocycloidal gear. As is known for hypocycloidal gears, the difference between the number of teeth on the pinion 32 and on the tooth ring 21 determines the number of revolutions of the shaft 29 required to rotate the pinion 32 once about its own axis. By suitable choice of this difference, a further, substantial, reduction in rotational speed is achieved.

Rotation of the pinion 32 on its axis is transmitted to the hinge element 3 by the Oldham Coupling previously described which causes the hinge element 3, and thus hinge element 2, to rotate relative to the casing I at a rotational speed lower than that of pinion 32.

In summary therefore, the drive of the motor 4 is greatly reduced by the aforedescribed gearing to an extent that the hinge elemeiits 2 and 3 may be rotated at a low speed relative to the casing I thus allowing controlled pivotal movement of the sections 5 and 9 of the articulated arm. The extent to which the arm is pivoted is obviously dependent on the length of time for which the motor is operated.

The embodiment of hinge described allows the sections of the arm to be pivoted up to 270C with respect to each other and during this movement the hinge has a constant high torque output.

WHAT WE CLAIM IS: 1. A power operated hinge assembly comprising a first cylindrical hinge element, a second hinge element relatively rotatable about the axis of said first hinge element, a motor, a first primary reduction gear for reducing the output speed of the motor, said first primary reduction gear having an output which is eccentric with respect to the axis of the first hinge element, a hypocycloidal gear formed of a tooth ring around the inside of the cylindrical hinge element and a pinion engaging said tooth ring and rotatably mounted about said eccentric output whereby rotation of said eccentric output nudges the pinion around the tooth ring, and means for transmitting the motion of said pinion to the second hinge element to effect said rotation of the second hinge element about the axis of the first hinge element.

2. Hinge assembly as claimed in claim 1 wherein the primary reduction gear is an epicyclic gear.

3. Hinge assembly as claimed in claim 2 wherein the epicyclic gear is a compound epicyclic gear.

4. Hinge assembly as claimed in any one of claims I to 3 wherein the means for transmitting the motion of the pinion to the second hinge elements is a constant velocity joint.

5. Hinge assembly as claimed in claim 4 wherein the constant velocity joint is an Oldham Coupling.

6. Hinge assembly as claimed in any one of claims 1 to 5 wherein the motor is a hydraulic motor.

7. Hinge assembly as claimed in claim 1 wherein the motor is an electric motor.

8. Hinge assembly substantially as hereinbefore described with reference to the accompanying drawing.

9. An articulated arm including a hinge assembly as claimed in any oneo claims 1 to 8.

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

Claims (9)

**WARNING** start of CLMS field may overlap end of DESC **. difference, a further, substantial, reduction in rotational speed is achieved. Rotation of the pinion 32 on its axis is transmitted to the hinge element 3 by the Oldham Coupling previously described which causes the hinge element 3, and thus hinge element 2, to rotate relative to the casing I at a rotational speed lower than that of pinion 32. In summary therefore, the drive of the motor 4 is greatly reduced by the aforedescribed gearing to an extent that the hinge elemeiits 2 and 3 may be rotated at a low speed relative to the casing I thus allowing controlled pivotal movement of the sections 5 and 9 of the articulated arm. The extent to which the arm is pivoted is obviously dependent on the length of time for which the motor is operated. The embodiment of hinge described allows the sections of the arm to be pivoted up to 270C with respect to each other and during this movement the hinge has a constant high torque output. WHAT WE CLAIM IS:

1. A power operated hinge assembly comprising a first cylindrical hinge element, a second hinge element relatively rotatable about the axis of said first hinge element, a motor, a first primary reduction gear for reducing the output speed of the motor, said first primary reduction gear having an output which is eccentric with respect to the axis of the first hinge element, a hypocycloidal gear formed of a tooth ring around the inside of the cylindrical hinge element and a pinion engaging said tooth ring and rotatably mounted about said eccentric output whereby rotation of said eccentric output nudges the pinion around the tooth ring, and means for transmitting the motion of said pinion to the second hinge element to effect said rotation of the second hinge element about the axis of the first hinge element.

2. Hinge assembly as claimed in claim 1 wherein the primary reduction gear is an epicyclic gear.

3. Hinge assembly as claimed in claim 2 wherein the epicyclic gear is a compound epicyclic gear.

4. Hinge assembly as claimed in any one of claims I to 3 wherein the means for transmitting the motion of the pinion to the second hinge elements is a constant velocity joint.

5. Hinge assembly as claimed in claim 4 wherein the constant velocity joint is an Oldham Coupling.

6. Hinge assembly as claimed in any one of claims 1 to 5 wherein the motor is a hydraulic motor.

7. Hinge assembly as claimed in claim 1 wherein the motor is an electric motor.

8. Hinge assembly substantially as hereinbefore described with reference to the accompanying drawing.

9. An articulated arm including a hinge assembly as claimed in any oneo claims 1 to 8.