GB2068059A - Grease nipples - Google Patents

Abstract

The invention provides a grease nipple of which the body 2, which has a bore 4 closed at one end by a spring- loaded ball 8, is of plastics material, and the bore is provided with an annular rib 16 or other abutment means e.g. ring 56 for retaining a spring in the bore, the arrangement providing that the spring may be inserted into the bore without, as is commonly required, a screwing action. <IMAGE>

Description

SPECIFICATION Oil or grease nipple The invention relates to an oil or grease nipple or body therefor, of the type, hereafter referred to respectively as a nipple or body of the type aforesaid, having a passage extending therethrough from an open end to an end closable by a ball urged against a seating by spring means and to methods of manufacturing same.

In the manufacture of grease nipples of the type aforesaid a problem has existed for a long time in that with metallic nipple bodies having integral retaining means for the spring means, it has been necessary to introduce the spring means past the retaining means by a screw action which is a tedious and time-consuming process, and this difficulty is obviated by the present invention.

According to one aspect of the invention there is provided a nipple body of the type aforesaid and composed of plastics material, wherein the passage has abutment means therein, the arrangement being that spring means may be inserted into the passage without screw action to urge a ball against a seating to close the open end and that the abutment means may act as an abutment for the thus-inserted spring means.

The abutment means may comprise a constriction formed by peening the body over the open end of the passage or by moulding an inwardly projecting rib on or around the surface of the passage.

Alternatively, the abutment means may comprise a groove formed in or around the surface of the passage. The spring means may comprise a compression spring and a retaining ring, the ring having a recess in or projection on its outer periphery for co-operating respectively with the rib or groove when inserted into the passage after the spring.

The plastics material may be thermoplastic and according to a particularly advantageous of the invention there is provided a method of manufacturing a grease or oil nipple having a body of the type aforesaid and comprising a thermoplastics material including the step of inserting a compression spring into the passage, maintaining the spring within the passage under compression, heat-softening the body at the open end of the passage, forming there a shoulder to provide an abutment for the spring, allowing the body to harden, and allowing the spring to expand to engage the abutment.

Embodiments of the invention will now be described by way of example and with reference to the accompanying drawings of which Figure 1 shows in longitudinal section a grease or oil nipple in one embodiment; Figures 2, 3 and 4 show similar views ofalterna- tive embodiments; and Figure 5shows in section a portion of the embodiment of Figure 1 together with a portion of a tool used in its manufacture.

The oil nipple shown in Figure 1 comprises a body 2 injection moulded from a thermoplastics orthermosetting resin material such as polycarbonate or acetal. A particularly suitable acetal plastics material is known underthetrade name of KEMATAL.

The body 2 is provided with a central bore 4 which terminates at one end in an inlet 6 which can be closed against loss of grease or oil by the urging of ball 8 against a seating defined by annular shoulder 10.

The upward urging of the ball 8 against the shoulder 10 is effected by a compression spring 12 which extends along the bore 4 to the open end 14 thereof.

At the open end 14 the plastics material of the body 2 is peened over at the rim of the bore to provide an annular abutment 16 against which the lower end of spring 12 can press.

In manufacture of the nipple, the body 2 is formed by injection moulding, and first the ball 8 and then the spring 12 are inserted into the bore 4, the resilience of the plastics material of the body allowing them to be forced past the abutment 16 although the compressive force of the spring 12 when located in the bore against the ball 8 in its uppermost position is insufficient to force it back over the abutment 16 so that in use it is retained within the bore.

In an alternative embodiment shown in Figure 2, the abutment 16 may be formed in the moulding process.

In the embodiment shown in Figure 4the bore 20 is moulded with an annular groove 52 into which the outwardly projecting annular rib 54 of retaining ring 56 engages, the rib 54 having been allowed to enter the bore 20 by the resilience of the plastics body as previously indicated. In place of the ring 56, the spring 40 may be formed at its lower end with a coil of such diameter as to engage in the groove 52.

In the embodiment shown in Figure 4 the body is formed with an integral "washer" 58. The plastics material of which the body is formed is coloured, thus allowing colour-coding of nipples according to, for example, the frequency of greasing required.

The grease nipple shown in Figure 3 has a ball-seating shoulder 58 set back from inlet 38 as is conventional for grease nipples. The spring 40 holding ball 42 against the seating is retained in a compressed state by retaining ring 44 which in turn is kept in position in bore 46 by the co-operation of annular groove 48 in the ring with annular rib 50 formed as a protrusion into bore 46 in the moulding of the nipple body. In assembling the components of the nipple, the ball and then the spring are first introduced into the bore. Then the ring 44 is forced into the bore until the rib 50 locates in the groove 48 at which position spring 40 is in a state of compression.

Where the body 2 is formed of thermoplastics material, a method of manufacture preferably involves the initial formation of a bore 20 which, as shown in Figure 5, is of constant diameter to the outside end 22. The ball (not shown) and the spring 12 are thus readily inserted into the bore by means of an inserting tool 24which at its forward end 26 is so dimensioned as to fit in the bore 20 and at its forward edge 28 is shaped to engage the spring 12 on movement in the direction of arrow 30 and carry the spring into the bore 20.

As the forward end 26 of the tool 24 continues to enter the bore 20, an annular shoulder 32 of the tool 24 engages with the rim of the bore at the end 22. An electric heating element is incorporated in the tool 24 at the shoulder 32 and by this means heat is applied to the rim of the bore 20. The plastics material becomes softer by the heating, and by reason of the shape of the shoulder 32 the softened plastics material is displaced inwardly of the bore as shown by dotted line 34.

Only sufficient heat is applied to produce the necessary degree of softening and deformation of the rim after which the heating current is discontinued so that the shoulder 32 cools and the body 2 solidifies at the deformed rim of the bore 20 leaving an annular abutment 36 of solid plastics material.

The tool 24 is then withdrawn from the body and the spring 12 is allowed to expand until it abuts on the abutment 36 and is held thereby within the bore 20.

Claims (10)

1. A nipple body of the type aforesaid and composed of plastics material, wherein the passage has abutment means therein, the arrangement being that spring means may be inserted into the passage without screw action to urge a ball against a seating to close the open end and that the abutment means may act as an abutment for the thus-inserted spring means.

2. A nipple body according to Claim 1 wherein the abutment means comprises a constriction formed by peening the body over the open end of the passage.

3. A nipple body according to Claim 1 wherein the abutment means comprises a constriction formed by moulding an inwardly projecting rib on or around the surface of the passage.

4. A nipple body according to Claim 1 wherein the abutment means comprises a groove formed in or around the surface of the passage.

5. A nipple body occording to Claim 3 or Claim 4 wherein the spring means comprises a compression spring and a retaining ring, the ring having a recess in or projection on its outer periphery for co operating respectively with the rib or groove when inserted into the passage after the spring.

6. A nipple body according to any one of the preceding Claims wherein the plastics material is thermoplastic.

7. A method of manufacturing a grease or oil nipple having a body of the type aforesaid and comprising a thermoplastics material including the step of inserting a compression spring into the passage, maintaining the spring within the passage under compression, heat-softening the body at the open end of the passage, forming there a shoulder to provide an abutment for the spring, allowing the body to harden, and allowing the spring to expand to engage the abutment.

8. A nipple body of plastics material substantially as described with reference to the drawings.

9. A nipple having a body of plastics material substantially as described with reference to the drawings.

10. A method of making a nipple of the type aforesaid having a body of plastics material substantially as described with reference to the drawings.