US3895561A

US3895561A - Fluid activated vibratory device

Info

Publication number: US3895561A
Application number: US388914A
Authority: US
Inventors: Jan Frederik Felderhof; James William Alfred Westwood
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-08-19
Filing date: 1973-08-16
Publication date: 1975-07-22
Anticipated expiration: 1992-07-22
Also published as: DD116765A5; FR2196595A5; AU5927273A; DE2341219A1; CA994189A; DE2341219B2; IN139689B; JPS5627305B2; JPS4986960A; SU640653A3; CH594449A5; AU474607B2; GB1452888A; NL7311386A; IT996112B

Abstract

A vibratory device comprising a hollow cylinder and a piston reciprocating in the cylinder is provided with a fluid channel system for deriving from the fluid pressure performances other than plain reciprocation of the piston.

Description

United States Patent Felderhof et al.

[451 July 22, 1975 FLUID ACTIVATED VIBRATORY DEVICE Inventors: Jan Frederik Felderhof, Voorburg,

Netherlands; James William Alfred Westwood, Upton upon Severn. England Filed: Aug. 16, 1973 Appl. No.: 388,914

Foreign Application Priority Data Aug. 19, 1972 United Kingdom 38770/72 Aug. 19, 1972 United Kingdom.... 38771/72 Aug. 22, 1972 United Kingdom 38998/72 LS. Cl. 91/20; 91/234; 91/335; 91/437; 92/85 Int. Cl. F01] 21/02 Field of Search 91/234, 341, 335, 232, 91/20, 437

[56] References Cited UNITED STATES PATENTS 1,940,388 12/1933 Callahan 91/234 2,797,664 7/1957 Swanson 91/234 3,023,738 3/1962 Burgess, Jr..... 91/234 3,601,009 8/1971 Burgess, 11* i 91/234 3,653,296 4/1972 Dexter 91/335 Primary ExaminerPaul E. Maslousky [57] ABSTRACT A'vibratory device comprising a hollow cylinder and a piston reciprocating in the cylinder is provided with a fluid channel system for deriving from the fluid pressure performances other than plain reciprocation of the piston.

18 Claims, 9 Drawing Figures PATENTEDJUL22 ms 1885581 SHEET 1 v FIG-1 zuF u, 10

PATENTEDJUL 22 1915 SHEET FIG.5

FIG. 9

FLUID ACTIVATED VIBRATORY DEVICE The invention relates to a vibratory device, consisting of a combination comprising a hollow cylinder terminated by end plates, passages for a gaseous pressure fluid. in which passages are arranged ports for inlet to and exhaust from the cylinder, a piston which is reciprocably movable in the cylinder in and out an axial position in which the piston establishes communication between an exhaust port and a working chamber in the cylinder in front of the trailing side of the piston when moving to said axial position, the pressure fluid periodically moving the piston to said position when acting on said trailing side and building up counter-pressure energy at the opposite side of the piston. Such devices are used for example with vibratory conveyors.

Devices of this kind are known in which the piston is of the double action type and in which a single inlet port is arranged and two exhaust ports disposed equidistantly on either side of the inlet port, the piston having two passages whereby the inlet port can communicate with the working chamber in either end of the cylinder. It is also known to form either or both of the inter-engaging cylindrical surfaces of the piston and cylinder from a material having a low co-efficient of friction and to run the device without an additional lubricant between the surfaces. Nevertheless, there is still a need for devices of higher performances in relation to their weight and costs.

An object of the invention is therefore to provide a vibratory device of the kind specified which can be operated more efficiently and economically in relation with the supplied pressure, which is operable over a wide range of frequencies and amplitudes and which is suitable for transmittance of vibratory energies of varied intensity.

It is also an object to provide such a device which has small dimensions in terms of its capacity to transmit energy and in terms of costs of manufacturing such device.

A vibratory device according to the invention is provide with fluid channel means which enable to derive from the pressure fluid also other functions than a plain reciprocation of the piston, such as cooling, control of readiness to start. control of preferred direction of energy transmittance, as will be elucidated herebelow.

The invention will now be described by way of example with reference to the accompanying drawings in which:

FIG. I is a crosssectional side elevation view of a vibratory device constructed in accordance with the invention:

FIG. 2 is an end elevation crosssectional view taken on the line II-II of FIG. 1;

FIG. 3 is a cross-sectional side elevation view ofa further embodiment of the invention;

FIG. 4 is a cross-sectional side elevation view of an extended version of the FIG. 3 construction;

FIG. 5 is a cross-sectional side elevation view of a yet further embodiment of the invention;

FIG. 6 is a cross-sectional side elevation view of the cylinder of another embodiment of the invention;

FIG. 7 is a crosssectional side elevation view of the cylinder of yet another embodiment of the invention;

FIG. 8 is a cross-sectional side elevation view of a part of the cylinder of yet another embodiment of the invention; and

FIG. 9 is a cross-sectional side elevation view of a multipiston embodiment of the invention.

Referring to FIGS. 1 and 2 of the drawings. there is shown a cylinder 10 closed at its ends by

end plates

11 and 12 respectively, which are secured by bolts 13. A radially disposed inlet port 14 for a fluid such as pressurized air is positioned mid-way between the ends of the cylinder. Two radially disposed

outlet ports

15 and 16 are situated in the cylinder wall with their axes at right angles to the axis of inlet port 14. These ports are axially disposed at equal distances on either side of the inlet port 14. In other embodiments of the invention, the

outlet ports

15 and 16 may be situated at any radial position in the cylinder wall so long as they are equally axially spaced on either side of the inlet port 14.

Within the cylinder there are two axially spaced bearing sleeves l7 and 18 defining between them an annular groove 19 which communicates with the inlet port 14.

The sleeves in this example are made from polytetrafluoroethylene. Another example of a material from which the bearing sleeve may be made is lead bronze which is impregnated with graphite. Such a bearing sleeve can be used as a bearing without any additional lubricant.

Axially aligned with the

respective outlet ports

15 and 16 and extending around the respective outer surfaces of the sleeves l7 and 18 are two further

annular grooves

20 and 21. These grooves are situated mid-way between the ends of the sleeves respectively and communicate each with an opening 22 in the sleeves respectively. The openings 22 extend into the internal surface of the respective sleeves l7 and I8 and are p0- sitioned so as to be diametrically opposite to the respective outlet ports 15 and I6.

Mounted for axial sliding movement within the sleeves is a piston 24, which has two L-shaped passageways and 26. Each of these passageways has an axially extending portion and a radially extending portion and communicate with the

opposite working chambers

27 and 28 in the cylinder respectively. When the piston moves axially in one direction from its central position as shown mid-way between the ends of the cylinder, one of the passageways communicates with the groove 19. Similarly, when the piston 24 moves in the other direction, the other passageway communicates with the groove 19. The respective axial portions of the

passageways

25 and 26 are over half as long as the piston 24. When the piston 24 is in its central position as shown, neither of the

passageways

25 and 26 can communicate with the groove 19. However, when pressureized air is applied to the inlet port 14, some leakage flow between the piston and the internal surfaces of the sleeves can take place, with preference for the air reaching one of the

chambers

27 and 28 directly or after passing through one of the

passageways

25 and 26, so as to build up a slight overpressure in one of the chambers. A special leak groove 29 of very small cross-sectional area provided in the surface of the piston 24, for the device to start to operate.

The pressurized air expands in the

chambers

27 and 28 and flows to the exhaust ports 15 and I6 respectively through the

circumferential grooves

20 and 21 respectively cooling effectively the sleeves I7 and 18, respectively.

Numeral 30 denotes a mounting ear.

In use, pressurized air is applied to the inlet port 14. Air will then reach one end of the cylinder through one of the

passageways

25 and 26. This will cause the piston to move. When the piston has moved a predetermined axial distance under the action of this pressure, the other passageway will communicate with the groove 19 and the inlet port 14 and thus admit pressurized air to the other end of the cylinder. The rate of vibration of the piston is principally dependent upon the pressure of the air entering and the mass, or inertia, of the piston.

Referring to FIG. 3 there is shown a vibratory device similar to that shown in FIGS. 1 and 2 of the drawings but with the cylinder formed from three

annular portions

31, 32, and 33, secured together by bolts 13'. There is shown in FIG. 4 a vibratory device which is an extension of the FIG. 3 construction, the cylinder being composed of five annular portions 34 to 38 respectively secured together by bolts 13. This longer version of the vibratory device accommodates a larger piston and for a given inlet pressure this provides slower vibration and higher power. The outlet ports in the wall of the cylinder are not shown in FIGS. 3 and 4. The end plates 41 and 42 of the FIG. 3 construction have respective central through

holes

43 and 44. Connected to the end plates 41 and 42 and communicating with the

holes

43 and 44 are respective L-shaped

pipe adaptors

45 and 46 which are interconnected at their outer ends by a U-shaped tube 47, which is provided with a control valve 48, the

parts

45, 46, 47 forming a by-pass between the working chambers. In the FIG. 4 embodiment a corresponding by-pass 49 is formed by holes drilled in the end plates 39 and 40 and in the annular portions 34-38. The by-pass 49 is at either end provided with

control valves

50 and 51 respectively. With the interconnection of the working chambers the frequency and amplitude of the vibrations produced by the device can be adjusted.

Referring to FIG. 5, there is shown a device similar to the device of FIG. 1, however, the FIG. device has a cylinder composed of three

annular portions

61, 62, 63 and futher has

exhaust ports

66 and 67 respectively, which are provided with respective

adjustable throttle valves

68 and 69. Each of the

valves

68, 69 has a central member 70 which comprises a frusto-conical part 71, a hexagonal flange 72 formed integrally with the conical part 71 on its larger end, and respective axially aligned threaded

cylindrical portions

73 and 74 extending from the smaller end of the conical part 71 and the flange 72 respectively. The cylindrical portions 74 of the

valves

68 and 69 engage screw threads on the internal peripheries of the

outlet ports

66 and 67 respectively and the flanges 72 abut against outer edges of the

ports

66 and 67. Extending axially through the cylindrical portion 74, the flange 72 and the frusto-conical part 71 of each of the

valves

68, 69 is a bore 76. This bore communicates with a through cross drilling 77 which extends transversely of the bore 76. Surrounding the frusto-conical part 71 is a cap 78 having a stepped bore 79 the larger section of which is tapered so as to be corresponding in shape to the conical part 71. The smaller section of the stepped bore 79 is screw-threaded and engages the screw thread of the cylindrical portion 73 of the central member 70. Rotation of the cap 78 varies the distance between the complementary tapered surfaces and thus provides a variable restriction to any fluid flowing out of the respective exhaust port and along the bore 76 and the drilling 77. The exhausting air is thus directed back over the outer surface of the vibratory device for cooling purposes. A locking nut 80 engages the outer end of the cylindrical portion 73, to lock the cap 78 in position thereon.

By means of these

throttle valves

68, 69, the restrictions in the

exhaust ports

66 and 67 respectively can be adjusted and thus the frequency and amplitude of the oscillation of the piston controlled. An increased restriction results in a rise of the frequency and a reduction of the amplitude.

The

throttle valves

68, 69 can be adjusted differently. whereby the average pressure in one working chamber will differ from that in the other working chamber, resulting in a preferred direction of energy transmittance.

A similar effect will be brought about by inlet or exhaust ports of different diameter and, or, a difference between the respective distances of the exhaust ports to the inlet port of the cylinder seen axially thereof. In the FIG. 6 embodiment the

exhaust ports

81, 82 in the

inner sleeves

83 and 84 respectively are at unequal distances from the inlet port 85 and the annular groove 86, the

exhaust ports

87, 88 in the outer cylinder being correspondingly positioned. In the FIG. 7 embodiment the

exhaust ports

91, 92 in the

inner sleeves

93 and 94 respectively and the corresponding

exhaust ports

97, 98 in the outer cylinder wall have a different diameter. but equal distances from the inlet port and groove 96.

Referring now to FIG. 8, there is shown a part of an embodiment in which the cylinder. composed of an outer cylinder wall and sleeves 111, is closed at its end by and end plate 112 secured by bolts 113. In a central screw threaded bore in the plate 112 is fixed a spring device 114, acting in the embodiment shown with compressed air, introduced and regulated in pres sure via the conduit 115, which spring device can also be of the metal spring type. The piston rod 116 cooperates each cycle of vibration with the piston, which is not shown. By means of the acting air pressure in the device 114 the characteristics of the created vibration can be regulated. A spring device 114 can also be fitted at the opposite end of the

cylinder

110, 111 and can be combined with other control means as described hereabove.

In FIG. 9 there are shown three axially aligned interconnected vibrators which act as a single vibratory unit.

The cylinders are each composed of an outer cylinder wall consisting of three

annular parts

121, 122, I23, and

inner sleeves

124, 125, each having an annular groove 126 for communication between an exhaust port in a sleeve and a diametrically opposed exhaust port in the surrounding annular outer wall part, which parts are not shown. In each of the interconnected vibrators is mounted a piston 127 provided with two L- shaped

passageways

128 and 129 for the periodical communication between the working chambers at either end of the piston with the inlet port 130 via the annular groove 131. The adjacent pistons are joined by a rod 132 which has screw-threaded ends 133 and 134 respectively, which threadedly engage tapped bores in the pistons respectively.

Respective flats

133a and 134a are indicated adjacent either end of the rods 132 to enable gripping of the rod when screwed to a piston.

The rod 132 between the intermediate piston 127 and the piston 127 at the right side in the figure is journalled at around its mid-portion by a dry bearing sleeve 135 secured in the separating plate 136. The rod 132 joining the piston 127 at the left hand side of the figure with the intermediate piston is journalled in a pair of seals 137, each comprising a ring 138 of shallow rectangular cross-section surrounded by an O-ring 139, which seals 137 are mounted in the separating plate 140. The

end plates

141 and 142 are secured by bolts 143 further passing through holes in the

annular parts

121, 122, 123 and the separating

plates

136, 140. In the end plate 142 is mounted a dry bearing sleeve 144 through which passes a piston rod 145 for joining of the combined pistons 127 to another device, not described herewith.

Pressurized air introduced through the respective inlet ports 130 will cause the pistons 127 to move in unison, each controlling the flow of the air just as described in relation with the other embodiments.

An advantage of the multi-piston device, when the pistons are rigidly united, is that each of them can be short without danger of canting which could cause high friction and quick wear. A special advantage is that a multi-piston device, compared with a single piston device has a greater piston area on which the pressure fluid can act in relation to piston weight and lengths of the channels for the flow of the fluid, and thus the resistance to this flow, resulting in greater frequency of the vibration and higher energy transmitted.

We claim:

1. A vibratory device comprising a hollow cylinder with terminal end plates, an inner sleeve fitted in said cylinder and extending between said end plates, said cylinder having an inlet for a gaseous pressure fluid, said sleeve having an inlet opening in registry with said inlet in the cylinder for flow of the pressure fluid therethrough, and a piston slidably mounted in said sleeve for undergoing reciprocating movement therein, said inner sleeve having a pair of axially spaced exhaust ports, said inner sleeve and cylinder defining two circumferential passages therebetween each in axial registry with a respective exhaust port, said cylinder having two outlet ports each in communication with a respective circumferential passage and therethrough with a respective exhaust port, each outlet port in the cylinder being circumferentially displaced with respect to the associated exhaust port in the inner sleeve, said piston being provided with two passageways, each for establishing communication between the inlet opening in the sleeve and a respective working chamber formed between one end of the piston and one terminal end plate, said piston in the course of reciprocating movement passing through respective axial positions in which the piston successively covers and uncovers each exhaust port in the inner sleeve.

2. A vibratory device according to claim 1, in which the piston in an intermediate position closes the inlet opening for the inlet of pressure fluid, and means allowing leakage flow of pressure fluid to one end side of the piston as compared to the other end side of the piston in its intermediate position.

3. A vibratory device according to claim 2, in which said means allowing leakage flow is an axial groove in said piston for said leakage flow.

4. A vibratory device according to claim 1 further comprising means at each of said outlet ports of said cylinder for individually and selectively varying fluid flow therethrough.

5. A vibratory device according to claim 4 wherein said means at each outlet port comprises an adjustable throttle valve.

6. A vibratory device according to claim 5 wherein each throttle valve includes an adjustable cap defining a stepped bore having an outlet facing the external surface of the cylinder and inclined theretowards to direct exhausted fluid onto the outer surface of the cylinder.

7. A vibratory device according to claim 1, in which said exhaust ports for the exhaust of the pressure fluid are arranged axially at either side of said inlet port for the inlet of the pressure fluid, such that the axial spacing between one exhaust port and the inlet port differs from the spacing between said inlet port and the other exhaust post.

8. A vibratory device according to claim 1 comprising a spring on at least one of the end plates for accumulation of counterpressure energy periodically derived from the pressure fluid and for cooperation with the piston for transmittance of said energy thereto, said spring being adjustable.

9. A vibratory device according to claim 8, in which said spring is an air pressure spring.

10. A vibratory device according to claim 1, comprising guide means for guiding exhausted fluid onto the outside surface of said cylindner for cooling the same.

11. A vibratory device according to claim 1, comprising a by-pass conduit connecting both said working chambers.

12. A vibratory device according to claim 11, comprising a regulating valve in said by-pass conduit.

13. A vibratory device according to claim 1, comprising a plurality of piston-cylinder combinations assembled in axial relationship, the pistons of adjacent combinations being connected by a connecting rod which passes through an end-plate of each of the adjacent cylinders.

14. A vibratory device according to claim 13, in which the pistons of adjacent combinations are rigidly connected.

15. A vibratory device according to claim 13, in which adjacent cylinders at their facing ends are terminated by one and the same end plate.

16. A vibratory device according to claim 1, wherein said cylinder comprises a plurality of cylindrical rings secured together in axial relationship.

17. A vibratory device according to claim 1 wherein said cylinder has a uniform cylindrical outer surface.

18. A vibratory device according to claim 1 wherein said exhaust ports in the inner sleeve and said outlet ports in the cylinder are in respective diametric opposition to one another.

Claims

8. A vibratory device according to claim 1 comprising a spring on at least one of the end plates for accumulation of counter-pressure energy periodically derived from the pressure fluid and for cooperation with the piston for transmittance of said energy thereto, said spring being adjustable.