GB2230839A - Buffer - Google Patents

Description

BUFFER 5 DESCRIPTION

The present invention relates to a buf f er and in particular, but not exclusively, to a buffer for a vehicle arranged for travel on a track.

Buffers are known, for tracked vehicles, which consist of a casing having a plunger thereinj which plunger has a buffer plate at one end, the plunger accommodates a set of springs and is secured with the aid of a fixing ring and a wedge. This arrangement is complex due to the shape of the individual components and also the lack of space within the buffer for housing the necessary springs, which lack of space.can restrict the type and quantity of springs that can be used.

The present invention seeks to provide a buffer in which the casing and the plunger have a simple shape and which can fit together, in secure engagement, without the need for additional components and also which provides an increased amount of space available for accommodating the necessary springs.

According to the present invention, there is provided a buffer comprising a casing and a plunger in the form of relatively slidable first and second members, the second member having a flange at one end and at least one shoulder at the other end, resilient means acting between the plunger and the casing, the first member having at least one first elongate recess extending along a substantial part of the axial length thereof and at least one second elongate recess extending only part-wayr less than said substantial part, along the axial length of the plungerF the first recess communicating with the second recess such that the plunger can engage the casing by reception of the at least one shoulder in the second recess after previously having been moved along the first recess.

Preferably, the first member comprises the plunger and is located around part of the casing such that an outer surface of the casing includes the shoulder and an inner surface of the plunger includes the first and second recess.

Preferably, the plunger is located around part of the casing such that an outer surface of the casing includes the shoulders and an inner surface of the plunger includes the recesses. The resilient means may comprise at least one compression spring.

Advantageously, the resilient means are located between respective bracket plates of the plunger and casing.

The invention is described further hereinaftert by way of example only, with reference to the accompanying drawings in which:

Fig. 1 is an axial section of half of a first buffer embodying the present invention; and Fig. 2 is an axial section of half of a second buffer embodying the present invention.

The buffer shown in Fig. 1 comprises a cylindrical casing 1 having an integral fixing flange 2 extending radially outwardly at the rear end; right hand side as shown in the drawings. The flange is used for attachment of the buffer toi for example, a tracked vehicle by screw means. The front end - left hand side as shown in the drawings - of the buf f er casing 1 is provided with two shoulders 3 (only one shown) diametrically opposite each other and each extending radially outwardly and which project by approximately the wall thickness of the buffer casing 1 and are of a similar curve in shape.

A cylindrical plunger 4 is provided which has two diametrically opposite continuous elongate and axially extending recesses 5 and two diametrically opposite axial recesses 6 which extend only approximately half the length of the plunger 4 from the front end. A fixing flange 7 is provided at the front end of, and integral with, the plunger 4. The form of the axial slots 5 and 6 correspond to the shoulders 3 and are located around the circumferential surface of the plunger 4 substantially at an angular separation of 90 degrees. The wall thickness of the plunger 4 is preferably uniform.

The casing 1 and the plunger 4 are engaged during formation of the buffer as follows:

The plunger 4 is moved over the casing 1 by the shoulders 3 being fed along the axial recesses 5, after which the plunger 4 is rotated, relative to the casing 1r through 90 degrees so that the shoulders 3 can then f it into the axial recesses 6 of the plunger 4. The plunger 4 and casing 1 can then be pulled apart in a telescopic manner until the shoulders 3 engage with seating surfaces 8 of the axial recesses 6.

The length of the cylindrical section of the casing 1 between the shoulders 3 and the fixing flange 2 should be at least equal to the axial length of the plunger 4 in order to provide for a secure connection between the casing 1 and the buffer plunger 4. The shoulders 3 are guided into the axial recesses 6 by the application of force and so preferably form a snug fit therein so that the plunger is then secured against rotational movement relative to the casing. The seating surface 8 of each of the recesses 6 functions to limit the travel of the plunger 4 over the casing by abutment with each of the corresponding shoulders 3.

The casing 1 also has an internal flange 9 at the back end for mounting a bracket plate 10. A set of springs (not shown) are located in the casing 1 and are accommodated between the bracket plate 10 and a further bracket plate 11 which is adjustably mounted on a guide pin 12 and secured thereon by a nut 13 located on the front face of the plate 11. The guide pin 12 has a stepped aperture 14 to accommodate a bolt 15 and its head 16. The plunger 4 is thus mounted in a manner allowing it to be adjusted in the axial direction against the force of the springs engaging the bracket plate 10 at the rear end of the casing 1.

A buffer plate 17 is secured to the fixing flange 7 of the plunger 4 by screw means 18 and has a recess 19 on the inside, for the partial accommodation of the bracket plate 11 and the nut 13.

According to the buffer of Fig. 2, the inner f lange 9 of the casing 1 is located inwardly of the rear end of the casing so that a smaller set of springs can be accommodated than in the buffer of Fig. 1. The buffer shown in Fig. 2 can therefore, for example, be designed for 30 or 5OkJ operation and that shown in Fig. 1, for example, be provided for 70kJ operation.

As shown in Fig. 2, it is possible to provide solely the bolt 15, without the guide pin 12. The head 16 of the bolt 15 is then located on the front side of the bracket plate 11. The bolt 15 also extends through an aperture in the plate 10 and is secured at the back by a nut 20. The travel of the plunger 4 in Fig. 2 should be at least equal to the distance of the bracket plate 10 from the rear end of the casing 1.

The casing 1 may have more than two shoulders 3, preferably being symmetrically distributed around the 35 circumference, and the number of respective axial k recesses 5 and 6 should then correspond accordingly.

The buffer plate 17 can also be designed as an integral part of the buffer plunger 4. In this case it will be necessary to provide a recess in the inner surface of the casing 1, extending in the circumferential direction, adjacent the buffer plate 17, so that the shoulders 3 can be transferred from the axial recesses 5 into the axial-recesses 6.

Claims (16)

1. A buffer comprising a casing and a plunger in the form of relatively slidable first and second members, the second member having a flange at one end and at least one shoulder at the other end, resilient means acting between the plunger and the casing, the first member having at least one first elongate recess extending along a substantial part of the axial length thereof and at least one second elongate recess extending only part-way, less than said substantial part, along the axial length of the plunger. the first recess communicating with the second recess such that the plunger can engage the casing by reception of the shoulder in the second recess after previously having been moved along the first recess.

2. A buffer as claimed in claim 1, wherein the first member comprises the plunger and is located around part of the casing such that an outer surface of the casing includes the shoulder and an inner surface of the plunger includes the first and second recess.

3. A buffer as claimed in claim 1 or 2, wherein a pair of said f irst recesses, a pair of said second recesses and a pair of said shoulders are provided.

4. A buf f er as claimed in claim 3, wherein the first and second recesses are respectively arranged symmetrically on the plunger.

5. A buf f er as claimed in claim 1, 2, 3 or 4, wherein the or each second recess is defined at one end by an impact surface for limiting the travel of the shoulder or shoulders therein.

6. A buffer as claimed in any one of claims 1 to 5, wherein the resilient biassing means is located between a first bracket plate, mounted on the plunger, 1 and a second bracket plate mounted on the casing, the mutual separation of which bracket plates is reduced by the stroke of the plunger.

7. A buf f er as claimed in claim 5, wherein the 5 bracket plates are inter-connected by bolt means.

8. A buff er as claimed in claim 7, wherein the bolt means comprises a guide pin extending f rom the first bracket plate and having a stepped bore therethrough, and a bolt extending f rom the second bracket plate into said borep the bolt having a head engageable with the step.

9. A buf f er as claimed in claim 7, wherein the bolt means is located through an aperture in the second bracket plate so that the separation of the bracket plates can be adjusted.

10. A buffer as claimed in any preceding claim, wherein a buffer plate is mounted on the plunger.

11. A buf f er as claimed in claim 10 j wherein the buff er plate is mounted on the plunger by way of screw means.

12. A buffer as claimed in any one of claims 1 to 9, wherein a buffer plate is formed integrally with the plunger.

13. A buffer as claimed in any preceding claim, wherein the first recess or recesses and second recess or recesses communicate by way of at least one recess connecting therebetween.

14. A buffer as claimed in any preceding claim, wherein the resilient means comprises at least one spring.

15. A buffer as claimed in claim 14, wherein the resilient means comprises a set of springs.

16. A buffer as claimed in any preceding claim substantially as hereinbefore described with reference to and as illustrated in Fig. 1 and Fig. 2 of the drawings.

4 Q.

i Published 1990atThePaterit Office. State House. 6671 I-lighHolborn, LondonWC1R4TP. Further copies maybe obtainedfrom The Patent Office. Sales Branch, St Mary Cray, Orpington. Kent BR5 3RD. Printed by Multiplex techniques ltd, St Mary Cray. Kent. Con. 1187