MXPA00000390A - Diaphragm piston valve - Google Patents

Abstract

A diaphragm piston having a diaphragm (52) between a body (50) and plate (56). A post (80) integral with and extends from the body through the diaphragm and the plate. A stop (66) is coupled to the post and limits the axial movement of the plate away from the body. A spring seat (78) is coupled to the post. A spring (76) is between the plate and the spring seat. The post includes a first shoulder (94) and the stop engages the first shoulder. The stop includes an orifice (68) shaped to move axially on the post past the first shoulder and rotate about the post and engage the first shoulder. The first shoulder has at least one circumferential recess (86) and the orifice in the stop includes a radial tab (70) smaller than the recess. A first lock (74) prevents rotation between the stop and the post. A second lock (62) is also provided preventing rotation between the plate and post. A unique stem (95) which guides the diaphragm piston in a valve seat is provided.

Description

DIAPHRAGM PISTON VALVE BACKGROUND AND SUMMARY OF THE INVENTION The present invention relates generally to pistons and more specifically to an improved diaphragm piston. Diaphragm pistons, for example for use in a service portion of a rail pneumatic brake valve, for example, a DB-60 brake valve available from New York Air Brake Corporation, are illustrated in Figures 1 and 2. The diaphragm piston includes a rubber diaphragm 24 which is held between a body 20 and a plate 28 which are held together by a post 10, having a head 12 and a threaded portion 16, which receives a nut 34. A spring 36 is placed between a spring seat 38 and the rear side of the plate 28.

A retainer 40, attached to the post 10 by the ring C 42, acts as a stop for the spring seat 38. A rod 45 is inserted into and attached to the post 10 when aligning the holes 19 and 46 and the pin 47. The rod 45 is received and guided in a bushing of a valve seat (shown in dotted lines). The rod 45 includes a shoulder 44 which can trap and wear out the valve seat bushing. Apart from the rubber diaphragm 24, all the parts are made of metal. Since all the parts are made of metal, the REF .: 32116 post 10 requires processing to create different areas, including threading. The number of parts increases the cost of the diaphragm piston. Also, there is no mechanism to prevent rotation of the elements among themselves. The present invention relates to a diaphragm piston having a diaphragm between a body and a plate. An integral post with and extending from the body through the diaphragm and plate. A stop engages the post and limits the axial movement of the plate away from the body. A spring seat attaches to the post. A spring is between the plate and the spring seat. The post includes a first shoulder and the stop engages the first shoulder. The stop includes a hole configured to move axially in the post beyond the first shoulder and rotates relative to the post and engages the first shoulder. The first shoulder has at least one circumferential recess and the hole in the stop includes a radial tab smaller than the recess. A first insurance prevents rotation between the top and the post. The lock includes a recess on both the top and the plate and a key is inserted into the recess when aligned. The spring retains the key in the recess. A second insurance is also provided by avoiding rotation between the plate and the post. The second insurance includes at least one pin and one recess, one of which is on the plate where the other of which is on the body. The post includes a second shoulder and the spring seat engages the second shoulder. The spring seat includes a hole shape for axially moving in the post beyond the second shoulder and rotating with respect to the post and engaging the second shoulder. The second shoulder for the spring seat includes a first portion having a first generally polygonal shape and a second portion having a second generally polygonal shape of more sides than the first shape. The hole in the spring seat is configured to move axially beyond the first portion of the second shoulder and rotate relative to the post and engage the second portion of the second shoulder. Preferably, the first polygonal shape is generally a triangular shape and the second polygonal shape is generally a hexagonal shape. A unique relationship is provided between the piston guide rod and the valve seat. A guide is integral with and extends from the body in an opposite direction from the direction in which the post extends from the body. A stem sits loosely in a hole in the guide. The rod includes a uniform diameter, with plane surfaces spaced circumferentially, which maintains guide contacts with a bushing of a valve seat over the entire stroke of the piston. While the diaphragm is made of rubber, the body, the plate and the lock that prevents rotation between the stop, are all made of plastic. The rod, spring seat and spring are made of metal. Other objects, advantages and novel features of the present invention will be apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a cross-sectional view of a diaphragm piston according to the prior art. Figure 2 is an exploded view of the diaphragm piston of Figure 1. Figure 3 is a cross-sectional view of a diaphragm piston according to the principles of the present invention. Figure 4 is an exploded view of the diaphragm piston of Figure 3. DETAILED DESCRIPTION OF THE PREVIOUS TECHNIQUE In addition to the previously described portions of the diaphragm piston of the prior art of Figures 1 and 2, further details will be explained. The post 10 includes a head 12 which forms a shoulder 13 with a body portion 14. A threaded portion 16 receives the nut 34. A recess 18 in the post 10 receives the ring C 42. The body 20 includes a hole 22 for receiving the body portion 14 of the post 10. The diaphragm 24 includes a hole 26. The plate 28 includes a hole 30 and a recess 32 for receiving the spring 36. The spring seat 38, retainer 40 and ring C 42, are also illustrated . The post 10 includes a guide 17 with a rod 45 inserted in the hole 11 and secured to the post 10 by the pin 47. The pin 47 is clamped in the rod 45 and is retained by holes 19. The rod 45 includes a head 43 and a reduced diameter position 48 with a shoulder 44 intermediate therebetween. The head 43 is the guide surface in the valve seat bushing (shown in dotted lines in Figure 1). The reduced diameter portion 48 with the bushing defines an air passage in the valve seat. Once the head 43 is outside the hub, there is no guide contact except if the rod 45 moves laterally. In this case, the shoulder 44 will trap the upper part of the valve seat causing damage during valve closing.

The assembly method of the prior art includes placing the diaphragm 24 between the body 20 and the plate 28 and inserting the through post 10. The nut 34 is threadedly received in the thread 16 of the post 10, clamping the diaphragm 24 between the body 20 and the plate 28. The spring 36 is then placed around the post 10 as well as the spring seat 38 and the retainer 40. The spring is then depressed until the ring C 42 is aligned and can be received within the recess 18 of the post 10. The rod 45 is then inserted into the post 10 and held by the pin 47. DETAILED DESCRIPTION OF THE PREFERRED MODALITIES A diaphragm piston of the present invention is illustrated in Figures 3 and 4. A diaphragm 52 is positioned between a body 50 and a plate 56. A central portion 57 of the plate 56 extends through a hole 54 in the diaphragm 52. The central portion 57 includes a hole 58 having both a pair of recesses 60 and a third recess 64. The recesses 60 receive the pins 62 projecting from the front of the base 50. This prevents rotation of the plate 56 from to the body 50. The body 50 also includes an integrally formed post 80. Post 80 has a first portion 82, with a flange 84 extending therefrom forming a first shoulder. A pair of circumferential recesses 86 are provided in the flange 84. A nut 66 includes a central hole 68 and a pair of radial tabs 70, only one of which is shown in Figures 3 and 4. The radial tabs 70 are aligned and received within the circumferential recesses 86 of the lip 84 and then rotate 90 ° such that the radial tabs are received under the shoulder 84 to accommodate the shoulder. This interlocks plate 56 to body 50 and diaphragm 52 therebetween. The nut or stop 66 also removes radial recesses 72. When one of the recesses 72 e :? the nut 66 is aligned with the recess 64 on the plate 56, a key 74 is inserted in both recesses in order to lock the nut 66 against rotation. The diaphragm piston also includes a spring 76 and a spring seat 78 with an orifice 79. The post 80 includes a reduced diameter section 88 extending from the flange 84. A generally hexagonal portion 92 and one. generally triangular section 90 form the end of the post 80. Although a hexagonal cross section 92 and a triangular cross section 90 are illustrated, both can be any polygonal shape, as long as the polygonal shape of 92 has more sides than 90. The hole 79 also is a polygonal shape and can for example be a triangle that will slide past the triangular position 90 and when turned, comes to rest against the shoulder 94 that is formed between the hexagonal shape 92 and the triangular shape 90. The hole 79 it can be for example a triangular shape or any irregular hexagonal shape. After the spring 76 is inserted around the post 80, an end is received in the recess 57 of the plate 56. The spring seat 78 is then also inserted onto the post 80 by compressing the spring 76. As discussed previously, the spring seat 78 moves past triangular section 90 on hexagonal section 92. Then it is rotated for example 60 ° until the body of spring seat 98 bears against shoulder 94. It will be noted that spring 76 also the key 74 engages the key 74 and retains it in the recesses 72 and 64. The body 50 also includes an integrally formed guide 81 including the hole 87. The guide 81 has a first shoulder 83 which is for example of a triangular shape or a hexagonal shape irregular. The guide 81 also includes a reduced diameter section 85. A rod 95 loosely seats within the hole 87. The rod 95 has two or more flat surfaces 96 that are circumferentially spaced and do not extend axially toward the ends. The portions of the stem 95 between the flat surfaces 96 are of the same diameter as the non-flattened head portion 97. In this way, the rod is in guide contact with the valve seat bushing (shown in dashed lines) during its total movement path. The planar surfaces provide an air passage of the same cross-sectional area as the reduced diameter portion 48 of the rod in the prior art 45 of Figures 1 and 2. This configuration of the rod 95 prevents entrapment and damage of the piston rod. the previous technique. The rod 95 can be employed by itself as a replacement of the rod 45 in the diaphragm piston of the prior art. A substantial reduction in costs results from making the base 50 with integral post 80, plate 56, nut 66 and key 74, from plastics. These molded products can be made of composite plastics, for example Verton. The diaphragm 52 is rubber and preferably reinforced with fabric or fabric. The spring 76 may be, for example, musical wire. The spring seat 78 can be made of steel. The spring 76 and the spring seat 78 can be coated with zinc. The rod 95 can be made of stainless steel. Although the present invention has been described and illustrated in detail, it will be clearly understood that it is by way of illustration and examples only and shall not be taken in any way by way of limitation. The spirit and scope of the present invention will be limited only by the terms of the appended claims. It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects to which it relates.

Claims (20)

1. CLAIMS Having described the invention as above, we will write CC? D p try the a__b__racb in the following claims: 1. A diaphragm piston characterized in that it comprises: a diaphragm between a body and a plate; an integral post with and extending from the body through the diaphragm and the plate; a stop coupled to the post and limiting the axial movement of the plate away from the body; a spring seat coupled to the post; and a spring between the plate and the spring seat.
2. 2. - A piston according to claim 1, characterized in that the post includes a first shoulder; and the stop includes a hole configured to move axially in the post beyond the first shoulder and rotate with respect to the post and engage the first shoulder.
3. 3. - A piston according to claim 2, characterized in that the first shoulder has at least one circumferential recess and the hole in the stop includes a radial tab smaller than the recess.
4. 4. - A piston according to claim 2, characterized in that it includes a first lock that prevents rotation between the stop and the plate.
5. 5. - A piston according to claim 4, characterized in that the latch includes a recess both in the stop and in the plate and a key inserted in the recesses when they are aligned.
6. 6. - A piston according to claim 5, characterized in that the spring retains the key in the recesses.
7. 7. - A piston according to claims 1 or 4, characterized in that it includes a second lock that prevents rotation between the plate and the post.
8. 8. - A piston according to claim 7, characterized in that the second latch includes at least one pin and a recess, one of which is on the plate and one of which on the body.
9. 9. A piston according to claim 1 or 2, characterized in that the post includes a second shoulder; and the spring seat includes a hole configured to move axially in the post beyond the second shoulder and rotates relative to the post and engage the second shoulder.
10. 10. A piston according to claim 9, characterized in that the second shoulder includes a first portion having a first generally polygonal shape and a second portion having a second generally polygonal shape of more sides than the first shape, and the orifice in the spring seat it is configured to move axially beyond the first shoulder portion and rotate relative to the post and engage the second shoulder portion.
11. 11. A piston according to claim 10, characterized in that the first portion has a generally triangular shape and the second portion has a generally hexagonal shape.
12. 12. - A piston according to claim 10 or 11, characterized in that the hole in the spring seat has at least three sides.
13. 13. - A piston according to claim 10 or 11, characterized in that the hole in the spring seat has six sides.
14. 14. - A piston according to claim 1, characterized in that the body with the post, plate and stop are made of plastic.
15. 15. - A piston according to claim 6, characterized in that the body with the post, plate, stop and key are made of plastic.
16. 16. A piston according to claim 1, characterized in that it includes an integral guide with and that extends from the body in a direction opposite to the direction in which the post extends from the body; and a rod seated in and extending from a hole in the guide.
17. 17. - A piston according to claim 16, characterized in that the rod has a uniform diameter with plane surfaces spaced and circumferentially displaced from one end of the rod.
18. 18. A valve having a valve element resting on a valve seat and a diaphragm piston according to claims 1 to 17, for moving the valve element relative to the valve seat.
19. 19. A valve having a valve element that rests on a valve seat and a diaphragm piston that includes a rod that runs in the valve seat and engages and moves the valve member with respect to the valve seat, The stem is characterized in that it comprises: a first portion of uniform diameter that engages the valve seat and the piston; and at least one flat surface extending along the axis and displaced from one end of the first portion to define a passage with the valve seat, while maintaining guide contacts between the first portion and the valve seat.
20. 20. - A valve having a valve element according to claim 19, characterized in that it includes a plurality of plane surfaces spaced circumferentially and displaced from one end of the first portion while maintaining guide contacts between the first portion and the valve seat .