GB2269204A - Pivot - Google Patents

Abstract

The pivot consists of a bracket (3) held on a fixed member and having a hole rotatably receiving a shaft (5) having one end adapted for connection to a pivotable member. The opposite end of the shaft is provided with a set of disk springs (7), positioning pieces (8) at opposite sides of the disk springs and a lock nut (9), rotatable with the shaft. When the shaft rotates, the positioning pieces and disk springs rotate along with it. When the rotating shaft stops rotating, it is fixedly positioned at that rotary angle due to the action of springing force of the disk springs. <IMAGE>

Description

Pivot The present invention relates to a pivot.

The Chinese Patent Office published on July 24, 1991 a patent application announcement of a utility model with Application Number 90224416.7 entitled "Pivot". The pivot consists of a bracket, a sleeve disposed in the bracket, and a rotating shaft in the sleeve. One end of the rotating shaft can be connected to a pivoting member and the other end is provided with a spring, a positioning piece and a jam nut. The pivoting mechanism can fix the rotating shaft at any rotary angle due to the springing force applied on the bracket by the action of the compression spring. Its principal disadvantages are: (1) It has a large number of parts and is bulky; (2) low service life for the compression spring so as to affect the service life of the pivoting mechanism.

The object of the present invention is to provide a pivot which is more compact in structure and less bulky and also has a long in service life.

The present invention consists of a bracket held on a fixed member and with a rotating shaft through hole, and a rotating shaft with one end capable of being connected to a pivoting member. An axially locating flange is provided in the middle of the rotating shaft. Its structure is featured in a set of disk springs disposed on the other end of the rotating shaft passing through the rotating shaft through a hole in the bracket, two positioning pieces and a jam nut located at the ends of this set of disk springs and rotatable synchronously with the rotating shaft.

The first improvement of the present invention is that the sleeve is eliminated and the compression spring is replaced by disk springs with compactness and good performance. The second improvement is that the disk springs will not be twisted and worn by each other when the rotating shaft rotates relative to the bracket since both ends of the disk spring set are held tight by positioning pieces rotatable synchronously with the rotating shaft, so as to insure the disk springs to carry on functioning under a better working condition. Therefore it has the distinct advantages of compact structure, less bulkiness and long service life.

Now, the present invention is further described in detail with reference to the accompanying drawings: Fig. 1 is an elevation of a pivot of the present invention, in which 1 is a mounting hole through which a bracket is connected to a fixed member and 2 is a mounting hole for connecting a rotatable shaft with a pivoting member.

Fig.2 is an end view of a positioning piece.

Fig.3 is an elevation of the shaft.

Fig.4 is a top view of the shaft as shown in Fig.3.

Fig.S is a sectional view taken along line A-A in Fig.4.

Fig.6 is a schematic diagram of parts disposed on the rotating shaft in arrangement sequence, and Fig.7 is a life time test curve of the pivot of the present invention.

Referring to the accompanying drawings, there is shown a bracket 3 and rotatable shaft 5 passing through a shaft hole in the bracket, an axially positioning flange 6 disposed in the middle of the shaft, a set of disk springs 7 disposed on the other end of the shaft passing through the shaft hole in the bracket, two positioning pieces 8 disposed on the ends of this set of disk springs and a jam nut 9 rotatable synchronously with the shaft. The bore of the positioning piece is drum-shaped. On the other end of the shaft, passing through the shaft hole in the bracket is ajournal 10 located at an inner side and matched to the rotating shaft through hole 4 in the bracket and a shaft body 11 with a drum-shaped cross section corresponding to the bore of the positioning piece.On the outside of the shaft body is defined an external thread 12 to match with the jam nut.

In order to reduce friction, shims 13 are provided on both sides of the bracket.

When the pivoting member rotates with the shaft 5 under the action of an external force, positioning pieces 8 and disk springs rotate along with them; when the pivoting member stops rotating, the shaft and the pivoting member are fixedly positioned at that rotary angle due to the springing action of the disk springs.

Shown in Fig.7 is a curve of torque in kg.mm versus number of times of to-and-fro openings plotted against test data of the present utility model obtained on a torque testing machine MOMENT OF TORSION aSO-9000) fabricated specially for this purpose. Under room temperature, the torque value for 1800 to-and-fro openings is measured and the stability of torque value in long duration use is recorded. It has been proved that the torque value of the described pivot of the present invention after 11,000 times of to-and-fro opening use maintains an expected figure of 60. After further continuous cumulative openings up to 22,000 times, the torque value is then lowered from 59 kg.mm to 58 kg.mm. This standard is outstanding amid products of the same kind.

The torsion stability may be considered as excellent.

The test conditions: (1) One to-and-fro open-close cycle is counted as one time.

(2) The opening angle is 1800.

(3) The opening rate is 09 to 11 times per minute.

(4) Test is made continuously during off ice time.

(5) Test temperature - room temperature.

(6) Specification of friction - 50 - 60 kg.mm.

The test data: KG.MM

Times 0 250 500 750 10001500 2000 Value 60 60 60 60 60 60 60 2500 3000 4000 5000 6000 7000 8000 9000 60 60 60 60 60 60 60 60 10000 12000 13000 14000 15000 j 16000 17000 60 59 59 59 59 59 59 18000 19000 20000 21000 22000 23000 24000 59 59 59 59 59 58 58 25000 26000 27000 28000 29000 30000 58 58 58 58 58 58 58 32000 33000 34000 35000 36000 37000 38000 58 58 57 57 57 39000 40000 final average value.

The present invention provides a pivot which is not only compact in structure and low in cost but also convenient in use and long in service life.

Claims (3)

1. A pivot consisting of a bracket for fixing on a fixed member on which is rotatably mounted a shaft having one end adapted for connection to a pivotable member, the shaft having disposed thereon a set of disk springs, positioning pieces located at opposite sides of the disk springs, and a jam nut, rotatable synchronously with the shaft.

2. A pivot according to Claim 1, wherein a bore of each positioning piece is drum-shaped, a journal portion is located on the shaft at an inner side and matched to a hole in the bracket which receives the shaft, the shaft having a portion of drum-shaped cross section corresponding to the bore of each positioning piece, the shaft portion having an external thread matched to the jam nut.

3. A pivot substantially as herein described with reference to the accompanying drawings.