US2030936A - Vibrator - Google Patents

Description

Feb. 18, 1936.

G. B. PICKOP VIBRATOR Filed Jan. 29, 1935 2 6g/g3. KTS I A2Z /0 24 Z5 @I Z A 1 Irlllllllrln 'l Half?? Patented Feb. 18, 1936 UITED STATES PATENT FFICE 11 Claims.

This invention relates to vibrators and more especially to that class of such tools wherein a piston is reciprocated in a cylinder by means of a fluid under pressure, such as compressed air, for example. I have shown my invention applied to such a reciprocating compressed air vibrator as is commonly employed in foundries in connection with loosening patterns or pattern plates, or rapping flasks in order to remove castings or patterns from molds.

It has been quite common in the past to employ in such vibrators a spring which is mounted at one end of the cylinder and acts upon the piston to urge it against the opposite end of the cylinder when the fluid pressure is shut oi and the piston comes to rest. It is, in the ordinary form of vibrator, necessary to have the piston come' to rest at one end of the cylinder in order that it may start when the air pressure is turned on. The reason for this is that when the compressed air is shut off during the operation of the ordinary vibrator, there will of course be a certain amount of compressed air left in the inlet tube which must exhaust itself, so that the piston will not necessarily stop instantaneously at the position occupied when the air is shut off.

As a result, the piston starts in its travel over another stroke and usually reaches a point midway between the ends of the cylinder wherein the air coming in through the intake passage is permitted to leak by to enter both ends of the cylinder, and at the same time the exhaust ports are slightly opened to a sufficient extent to per- -mit leakage of this air from the cylinder, and it is in this position that the piston is likely to stop. If the air is again turned on, the piston will be in a balanced condition, as some of the air will leak by into both ends, and likewise leak out of both exhaust ports, and hence the operation of the vibrator will not start.

The present invention has for one of its objects the provision of a vibrator with which it will be unnecessary to employ a spring and which will be so constructed that the piston will always stop in a position from which it will readily start when the pressure fluid is again supplied.

Another object of the invention is the provision of a springless self-starting vibratory tool of the cylinder and piston type which will be simple in construction, economical to manufacture, and positive in its operation.

Still another object of the invention is to provide a very simple form of vibrator of the piston and cylinder type which will be so constructed 'that the piston will stop in a position to be moved by the mechanical impact of the entering compressed fluid.

To these and other ends, the invention consists in the novel features and combinations of parts Ato be hereinafter described and claimed. v5

In the drawing:

Fig. 1 is a top plan View of a vibrator embodying my invention;

Fig. 2 is a sectional View of the vibrator showing the piston in the position which it will u'su- 10 ally occupy when in repose;

Fig. 3 is a view similar to Fig. 2 but Showing the parts in another position with the piston at one end of its stroke;

Fig. 4 is a sectional view on line lI--II of Fig. 15 2; and

Fig. 5 is a View of the piston member alone.

The tool which I have chosen to illustrate and describe as a preferred embodiment of my invention comprises a casing IIl bored out to pro- 20 vide a cylinder II, the ends of which are closed by the heads I2 and I3, which, as shown, may be threadedly secured to the vibrator body or casing I0. Within the cylinder, a reciprocatory piston I4 is disclosed which, as will be more fully explained hereinafter, is designed yto be operated by a fluid under pressure, such as compressed air, for example, so that it will be reciprocated in a back-and-forth movement to strike against the heads I 2 and I3 to set up vibra- 30 tions in the casing Ill, and through the attaching member I5 provided upon one of the end heads, vibrate the object I6 to which the member I5 is secured by the bolt I1.

The body or casing Iil is provided atits central 35 portion with a boss I8 having a threaded bore I9 communicating through a port 20 with the cylinder or chamber II. It will be understood that the hose or pipe line, or other device carrying the pressure fluid to operate the tool, will be 40 secured to the boss I8, the port 20 being the intake opening to admit pressure fluid to the cylinder II of the tool.

Upon each side of the boss I8, a single longitudinal bore is provided in the body of the casing 45 I0 extending parallel to the axis of the cylinder. These bores or passages are designated by the numerals 2l and 22 and each is connected with the cylinder by ports 23 and 24, which portslie relatively closely to the intake opening 20. The 50 passages 2l and l22 also communicate with the cylinder adjacent the ends of the latter by the ports 25 and 26.

The piston I4, shown more particularly in Fig.

5, is provided with a relatively reduced central -55 portion and end portions also reduced in diameter, leaving the intermediate portions 21 and 28 relatively enlarged so as to fit fairly closely the interior of the piston. Between the portions 21 and 28, the piston, as stated, is reduced in diameter to provide a relatively wide peripheral groove terminating at its ends in the shoulders 29 and 30 adjacent the portions 21 and 28.

The bottom 3| of a portion of this groove, that portion adjacent the part 21, as shown, is substantially parallel to the axis of the piston, while the bottom 32 of the remainder of this groove is inclined toward the axis of the piston, so that the shoulder 3i) is relatively wide as well as being abrupt. The part 3| joins the part 32 on a line which is slightly nearer the right-hand end ofY the piston than the left-hand end.

It will be apparent that when the piston is at one end of its stroke, the left-hand end, as shown in Fig. 3, for example, compressed air entering through the bore I9 and port 2D is permitted to enter the cylinder in the space between the shoulders 29 and 3l] of the piston. This air can then pass into the passage 22 through the port 24, as the latter port will be uncovered by the part 28 lof the piston. The air then passes downwardly through the port 26 into the end of the piston and drives the latter to the right. When the piston reaches the right-hand position, an exhaust port will be uncovered, as will be hereinafter explained, and the left-hand end of the cylinder will be permitted to exhaust.

The body I0 is provided with exhaust openings 33 and 34. It will be noted that the exhaust opening 34 is slightly smaller than the exhaust opening 33 and is also slightly farther from the end of the cylinder. For instance, if the center of the exhaust port 33 is l--ths inches from the end of the cylinder, I position the center of the opening 34 at a distance of two inches from the end of the cylinder, so, as will be understood, the piston must travel further toward the left to uncover the exhaust port 34 than it must travel toward the right to uncover the exhaust port 33. The result will be a slight unevenness in the energy of the blows imparted upon the ends vof the tool as there will be a more nearly complete venting or exhausting of the left-hand end of the cylinder than there will be of the righthand end of the cylinder. However, it is this unequal positioning of the exhaust openings in connection with the particular shape of the central part of the piston that enables me to provide a satisfactory springless vibratory tool of this character.

The operation of the device while in use is readily understood as the exhaust ports 33 and 34 function in the usual way, and it has already been explained that compressed air entering the port 20 will be carried to one end or the other of theicylinder by the passages 2| or 22, depending upon the position of the piston. It will, however, probably be helpful to explain the starting and stopping of the vibrator piston. When .the supply of compressed air is shut olf from the Vibrator, the piston being, for example, at one tend of the cylinder, as shown in Fig. 3, the compressed air remaining in the pipe and in the passages of the vibrator as well as in the left-hand end of the cylinder or chamber l l will tend to move the piston toward the right as the port 34 is uncovered and the right-hand end of the cylinder is vented. This movement to the right will continue until the piston reaches the position shown substantially in Fig. 2 wherein the exhaust port 33 has been opened to a sufficient extent to permit a slight amount of air to leak by. As the exhaust port 34 is slightly closer to the center of the vibrator body or at a greater distance from the right-hand end, this exhaust opening will be closed and the piston at the same time will be slightly nearer the left-hand end of the cylinder than the right, whereby the port 23 will be closed but the port 24 will be opened to a slight extent to permit a slight leakage of air into the passage 22. In this position there will be a balanced condition between the parts and it is found that this is the position at which the piston comes to rest when it does come to rest adjacent the center of the cylinder. It is of course apparent that if it should come to rest at either end of the cylinder, no diiculty will be encountered in its starting when the air is turned on.'

If, with the parts in the position shown in Fig. 2, the compressed air is turned on, there will of course be a sudden rush of air through the port 2S as the air within the cylinder adjacent this port and between the shoulders 29 and 33 of the piston has leaked out through the passage 22 and exhaust 33. This column of air will pass down the inclined surface 32 and strike against the abrupt shoulder 3E! and exert a mechanical push to move the piston to the right. This immediately moves the piston to a position in which the port 20 is uncovered and the vent port 33 closed so that the air passes to the left-hand end of the piston and immediately places it in operation.

While I have shown and described a preferred embodiment of my invention, it will be understood that it is not to be limited to all of the details shown, but is capable of modification and -variation within the spirit of the invention and within the scope of the appended claims.

What I claim is:

1. A vibratory engine or tool comprising a body provided with a cylinder and a piston mounted to reciprocate in the cylinder, said body being .provided with an inlet opening adjacent its central portion leading into the cylinder and also being provided with passages each communicating with the cylinder adjacent an intermediate portion thereof and adjacent one end thereof, the piston being vprovided with a recess adjacent its central portion adapted to effect communication between said inlet port and one or the other of said passages, and said recess having an inclined bottom surface terminating in an abrupt shoulder.

2. A vibratory engine or tool comprising a body provided with a cylinder and a piston mounted to reciprocate in the cylinder, said body being provided with an inlet opening adjacent its central portion leading into the cylinder and also being provided with passages each communicating with vthe cylinder, said body being provided with an inlet opening adjacent its central portion leading into the cylinder and also being provided with passages each communicating with the cylinder iii) adjacent an intermediate portion thereof and adjacent one end thereof, said piston being provided with a relatively wide annular groove intermediate its ends adapted to effect communication between said inlet port and one or the other of said passages, and said groove being deeper adjacent one end than the other and terminating at the deeper end in a relatively wide abrupt shoulder.

4. A vibrator comprising a body provided with a cylinder and a piston mounted to reciprocate in the cylinder, said body being provided with an inlet opening adjacent its central portion leading into the cylinder and also being provided with passages each communicating with the cylinder adjacent an intermediate portion thereof and adjacent one end thereof, the piston being provided with a recess adjacent its central portion adapted to effect communication between said inlet port and one or the other of said passages, said recess having an inclined bottom surface terminating in an abrupt shoulder, said cylinder being provided With exhaust ports adjacent the ends thereof, and one of said exhaust ports being at a greater distance from the end of the cylinder than the other exhaust port.

5. A vibrator` comprising a body provided with a cylinder and a piston mounted to reciprocate in the cylinder, said body being provided with an inlet opening adjacent its central portion leading into the cylinder and also being provided with passages each communicating with the cylinder adjacent an intermediate portion thereof and adjacent one end thereof, said piston being provided with a relatively Wide annular groove intermediate its ends adapted to effect communication between said inlet port and one or the other of said passages, said groove being deeper adjacent one end than the other and terrninating at the deeper end in a relatively wide abrupt shoulder, said body being provided with exhaust ports adjacent the ends thereof, and the exhaust port at that end of the body nearer said abrupt shoulder being nearer to the end of the casing than the other exhaust port.

6. A vibrator comprising a casing provided with a cylinder and a piston mounted to reciprocate in the cylinder, said casing being provided with exhaust ports adjacent the ends thereof and an inlet port adjacent its central portion, said piston being provided with a peripheral groove communicating with said inlet port, said casing being provided with passages to provide communication between said groove and the ends of the cylinder, said groovebeing deeper at one end than at the other to provide a relatively wide abrupt shoulder at the deeper end, and one of said exhaust ports being nearer the end of the cylinder than the other.

'1. A vibrator comprising a casing provided with a cylinder and a piston mountedto reciprocate in the cylinder, said casing being provided with exhaust ports adjacent the ends thereof and an inlet port adjacent its central portion, said piston being provided with a peripheral groove communicating with said inlet port, said c-asing being provided with passages to provide communication between said groove and the ends of theV cylinder said groove being deeper at one end than at the other to provide a relatively wide abrupt shoulder at the deeper end, and one of said exhaust ports being nearer the end of the cylinder than the other, the said one exhaust port also being at that end of the casing adjacent said relatively wide shoulder on the piston.

8. A vibrator comprising a casing having a cylinder and a piston mounted tol reciprocate in said cylinder, said casing having an air inlet port and means for delivering air entering said inlet port tol the ends of said cylinder, means effecting the stopping of said piston in a position from which it will be driven to one end of the cylinder when the motive fluid is turned on, said means including an exhaust port adjacent each end of the cylinder, one of said exhaust ports being nearer the end of the cylinder than the other, said piston having portions thereon closing said exhaust ports, and said portions terminating in planes substantially equidistant from the center of the piston.

9. A vibrator comprising a casing having a cylinder and a piston mounted to reciprocate in said cylinder, said casing having an air inlet port and means for delivering air entering said inlet port to the ends of said cylinder, means effecting the stopping of said piston in a position from Which it Will be driven to one end of the cylinder when the motive fluid is turned on, said means including an exhaust port adjacent eacn end of the cylinder, one of said exhaust ports being nearer the end of the cylinder than the other, and said piston being provided with a shoulder to receive, when in a position of rest, a mechanical impact from the pressure fluid When the latter is turned on.

l0. A fluid pressure vibrator comprising a casing provided with a cylinder and a piston mounted to reciprocate therein, said piston having an annular :groove in its surface. at a point intermediate its ends, there being an abrupt face at one end only of said groove, the casing being provided with an air inlet port in constant communication with said groove, and means for establishing intermittent communication between said port and the cylinder at one end o-f the piston.

11. A fluid pressure vibrator comprising a casing provided with a cylinder and a piston mounted to reciprocate therein, said piston having an annular groove in its surface at a point intermediate its ends, there being an abrupt face at one end only of said groove, and said groove having an inclined bottom surface extending from said face toward the surface of the piston, the casing being provided with an air inlet port in constant communication with said groove, and means for establishing intermittent communication between said port and the cylinder at one end portion thereof.

GEORGE B. PICKOP.

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