US3740018A

US3740018A - Safety control handle for air actuated equipment

Info

Publication number: US3740018A
Application number: US00221623A
Authority: US
Inventors: M Cleary
Original assignee: CLEMCO CLEMENTINA Ltd
Current assignee: CLEMCO CLEMENTINA Ltd
Priority date: 1972-01-28
Filing date: 1972-01-28
Publication date: 1973-06-19
Anticipated expiration: 1990-06-19

Abstract

A control handle for air actuated equipment is disclosed which includes means for preventing the control handle from being operated unintentionally as well as ''''dead man'''' safety features. An abrasive blasting system utilizing the control handle of this invention is described.

Description

ACTUATED EQUIPMENT [75] Inventor: Mark W. Cleary, San Francisco,

Calif.

[73] Assignee: Clemco-Clementina Ltd., San

Francisco, Calif.

[22] Filed: Jan. 28, 1972 [21] Appl. No.:'22l,623

[52] US. Cl. 251/94 [51] Int. Cl. Fl6k 35/00 [58] Field of Search 251/89 [56] References Cited UNITED STATES PATENTS 1,965,237 7/1934 Hawkins .I. 251/94 United States Patent 1 [111 3,740,018 Cleary v [4 June 19, 1973 SAFETY CONTROL HANDLE FOR AIR Primary Examiner-Henry T. Klinksiek Attorney-Robert W. Dilts [57] ABSTRACT handle from being operated unintentionally as well as dead man safety features. An abrasive blasting system utilizing the control handle of this invention is described. I

10 Claims, 8 Drawing Figures PATENTED 9375 SHEET]. BF 2 FIG 4 PA'IENIED JUN I 9 I975 smanr SAFETY CONTROL HANDLE FOR AIR ACTUATED EQUIPMENT BACKGROUND OF THE INVENTION This invention relates to a control handle for use in the control system of air actuated equipment, and more particularly, to a control handle including means for preventing the unintentional operation of the equipment.

The remote control of high-pressure air actuated equipment through the use of the high-pressure air it self is known in prior art. In the prior art, normally closed air actuated valves are provided in the equipment itself and, to control the system, a separate highpressure line extends from the source to a remote point at which a normally closed control valve is located. The control valve is manually actuated to pass high pressure air into a line leading to the air actuated valves on the equipment thereby opening such valves and actuating the equipment.

A more sophisticated version of the prior art system is disclosed in US. Pat. No. 3,201,901. As disclosed in this patent, the air actuated valves in the equipment are designed to be normally open and are closed or turned off" by the application of high-pressure air thereto. In such system an additional normally closed pilot valve is included in the equipment. The pilot valve is connected to the control valve and is designed to be actuated (opened) by high-pressure air passed through the control valve upon manual actuation of the control valve. When actuated by high-pressure air passing through the control valve, the pilot valve exhausts the high pressure air from the air actuated valves on the equipment allowing them to open and thereby actuate the equipment. In addition to requiring the use of an additional pilot valve, this system has the disadvantage of exhausting air from the high-pressure air source to the atmosphere when the equipment is in operation thereby tending to reduce the high-pressure air available for such operation.

The prior art systems were intended to provide a dead man" safety feature in that the manually operable control valve located at the remote point is designed to be normally closed when high-pressure air is applied thereto. Since the control valve located at the remote point will therefore automatically close in the absence of manual operation, it was assumed that if the operator became unconscious or disabled, the valve located at the remote point would automatically close to deactivate the equipment. Unfortunately, it has been found difficult to design a control valve which can be manually operated for extended periods without fatigue and yet will immediately return to its closed position automatically when not manually operated. Such valves have a tendency to stick in their open or operated position under the influence of the high-pressure air and if appropriate spring or other mechanical means are included to overcome such tendency to stick, then the continuous manual operation of the valve becomes more difficult and fatiguing. Furthermore, a control valve that is very easy to operate manually is also very easy to operate unintentionally.

It is an object of this invention to provide means other than a control valve for controlling air actuated equipment from a remote point.

It is another object of this invention to provide a manually operable control handle for controlling air actuated equipment from a remote point, which control handle cannot stick in its operated condition.

It is a further object of this invention to provide a control handle for the operation of air actuated equipment from a remote point, which control handle cannot be unintentionally operated.

It is yet another object of this invention to provide a control handle for the operation of air actuated equipment from a remote point through the use of highpressure air, which control handle cannot be unintentionally operated and yet may be manually operated without fatigue and without danger of sticking in its operated condition.

SUMMARY OF THE INVENTION The control handle of this invention comprises a solid body having a first passageway formed therethrough..

Means are provided for connecting high-pressure air to one end of such first passageway. A lever arm is movably mounted on the body and includes a sealing portion adapted to engage the other end of the passageway through the body. Spring means are included in the handle for mechanically biasing the lever arm so that the sealing portion thereof is out of engagement with the associated end of the first passageway through the body. A second passageway is provided through the body which intersects the first passageway therethrough and an axially movable pin having an enlarged head on one end thereof extends through such second passageway for axial movement therein. Retaining means are applied to the opposite end of the pin from the head thereof to limit the axial movement of the pin in the passageway to movement between opposite extremes. At one extreme ofits movement the head of the pin is positioned to prevent movement of the lever arm to bring the sealing portion thereof into engagement with the associated end of the first passageway and at the other extreme of its movement, the head of the pin is positioned to permit such movement of the lever arm.

BRIEF DESCRIPTION OF THE DRAWINGS The foregoing and other objects and features of the subject invention will be more fully understood from a reading of the following detailed description thereof in conjunction with the appended drawing wherein:

FIG. 1 is a side view in elevation of a control handle in accordance with one embodiment of this invention with the elements thereof shown in their normal or non-operated position.

FIG. 2 is a side view in elevation of the control handle of FIG. 1 with the elements thereof shown in their operated or manually actuated position.

FIG. 3 is a cross-sectional view taken along lines 33 of FIG. 1.

FIG. 4 is a cross-sectional view taken along lines 4-4 of FIG. 2.

FIG. 5 is a perspective view of a unit of air actuated industrial equipment, namely, an abrasive blasting unit in connection with which the control handle of this invention may be used with advantage.

FIG. 6 is a perspective view of a control handle in accordance with the teaching of this invention showing a typical mounting of such safety handle at a remote location.

FIG. 7 is a fragmentary view of the unit of air actuated equipment shown in FIG. 5, but indicating a different arrangement of control lines which may be used with a control handle according to the teaching of this invention.

. FIG. 8 is a perspective view of a control handle in accordance with the teaching of this invention mounted together with a suitable adapter for use in the system of FIG. 7 at a remote location.

DETAILED DESCRIPTION Referring to FIGS. 1 and 2, it will be seen that a control handle in accordance with the teaching of this invention comprises a solid body 10 formed to provide a passageway 11 therethrough. According to the embodiment of the invention as shown in FIGS. 1 and 2, the passageway 11 is L-shaped and has a first portion extending horizontally from the right-hand side of the body 10 to approximately the center of the body 10 and a second portion extending vertically from the center to the top of the body 10. The end of the passageway at the right-hand side of the body 10 is provided with appropriate means 12'including screw threads, for example, connecting a high-pressure air source (not shown) to the passageway 11. The other end 13 of the passageway 11 may be provided with an appropriate sealing means 14 for plugging or sealing the passageway 11 against the escape of high-pressure air therefrom.

The sealing means 14 is carried by an appropriate lever arm 15 movably mounted on the body 10. As shown in FIGS. 1 and 2, the end of the lever arm 15 adjacent the sealing means 14 may be pivotally mounted on the body 10 by means of an appropriate pin 16 pass ing through the lever arm 15 and body 10 and secured at its ends by appropriate retaining means 17. The end 18 of the lever arm 15 remote from the pivot pin 16 may be provided with an appropriate surface for engagement by the human hand in operating the control handle. As shown in FIGS. 1 and 2, the body 10 may be secured to an appropriate mounting plate 19 by means of screws 20. In this embodiment, a spring means 21 extends between the mounting plate 19 and the lever arm 15 and is adapted to urge the lever arm 15 to normally assume the position shown in FIG. 1.

Referring to FIG. 2, the manual application of force to the end 18 of the lever arm 15 with respect to the .mounting plate 19 will cause the lever arm 15 to rotate about the pivot pin 16 compressing the spring means 21 and bringing the sealing means 14 carried by the lever arm 15 into engagement with the end 13 of the passageway 11 at the top of the body 10. The engagement of the sealing means 14 with the end 13 of the passageway 11 at the top of the body 10 will seal the passageway 11 and prevent the escape of high-pressure air from the passageway 11 so long as force is applied to the end 18 of the lever arm 15 with respect to the mounting plate 19. If the manual application of force to the end 18 of the lever arm 15 with respect to the mounting plate 19 is released, the spring means 21, as well as the highpressure air in the passageway 11, will urge the lever arm 15 to rotate about the pivot pin 16 thereby moving the sealing means 14 away from the end 13 of the passageway 11 at the top of the body 10 and allowing highpressure air to escape from the passageway 11 to the atmosphere.

It will be seen that the presence of high-pressure air in the passageway 11 will tend to oppose the manual movement of the lever arm 15 to bring the sealing means 14 into engagement with the upper end 13 of the passageway 11. Since the spring means 21 also opposes such movement of the lever arm 15, it will be seen that the release of manual pressure on the end 18 of the lever arm 15 will immediately result in the exhaust of high-pressure air in the passageway 11 to the atmosphere. Furthermore, there are no moving parts, other than the lever arm 15, which could possibly stick or bind to thereby result in the retention of high-pressure air within the passageway 11 upon release of manual pressure from the end 18 of the lever arm 15. It will also be seen that the mechanical advantage provided by the length of the lever arm 15, and particularly the spacing of the end 18 thereof to which manual forces are applied from the pivot point 16, will enable the operation ofthe control handle through the application of relatively small forces. Thus the manual application of such forces to the end 18 of the lever arm 15 will not tend to be fatiguing to the operator of the handle.

However, the very fact that only a small amount of manual force is required to operate the control handle may result in the unintentional operation of such control handle. In fact, if the control handle is not permanently mounted but rather is adapted to be freely moved from one position to another, then there is the possibility that if the control handle is merely allowed to rest on a supporting surface in an inverted position from that shown in FIGS. 1 and 2, then the weight of the control handle itself might result in the operation thereof. This is particularly true where the control han dle is mounted on the end of a flexible hose such as that used in sand blasting equipment, since the weight of the hose will also be available to assist in the inadvertentoperation of the control handle.

To avoid such unintentional inadvertent operation of the control handle according to this invention, a safety button 25 is mounted inthe body 10 in such a way as to prevent movement of the lever arm 15 to bring the sealing means into engagement with end 13 of passageway 11 unless the safety button 25 is manually moved with respect to the body 10.

Referring specifically to FIGS. 3 and 4, it will be seen that the safety button 25 according to the teaching of this invention, comprises the enlarged head 25a of a pin 26 received in a passageway formed in the body 10 transversely of the passageway l l. The pin 26 is axially movable in the passageway 27 and may be held therein by a retainer ring 28 affixed to the opposite end of the pin 26 from the head 25a. As shown in FIGS. 3 and 4, the passageway 27 may be countersunk adjacent the enlarged head 25a so that such enlarged head 25a may be received within the body 10. As also shown in FIGS. 3 and 4, the enlarged head 25a may be provided with a portion of reduced cross-section which is in turn provided with a gasket means 29 adapted to provide a seal between the reduced portion of the enlarged head 25a and the passageway 27 when the enlarged head 25a is received within the body 10. According to this embodiment of the invention, the passageway 27 intersects the passageway 11 so that any high-pressure air present in passageway 11 is also present in passageway 27.

As shown in FIGS. 1 and 3, when the lever arm 15 is in the position shown in FIG. 1, then the air-pressure present in passageways 11 and 27 will act against the enlarged head 25a of the pin 26 causing such enlarged head 25a to project from the body 10. Since the enlarged head 25a is located directly below the lever arm 15, it will be in a position to prevent the lever arm 15 from being rotated about the pivot pin 16 toward the mounting plate 19 by engagement between the lever arm 15 and the outer periphery of the enlarged head 25a or safety button 25. Thus, in order to operate the control, the safety button 25 comprising the enlarged head 25a of the pin 26 must first be pushed into the body by manual pressure exerted by the fingers, for example. The amount of manual pressure required will be small since the pressurized air present within the passageways 11 and 27 will be exhausted to the atmosphere through the upper end 13 of the passageway 1 1. Once the safety button 25 has been pushed into the body 10, the lever arm 15 may be rotated about the pivot pin 16 to the position shown in FIG. 2.

Referring to FIGS. 2 and 4, it will be seen that a portion or flange of the lever arm 15 will overlap the safety button 25, holding it in its position within the body 10' as shown most clearly in FIG. 4. When the sealing means 14, carried by the lever arm 15, engages the upper end 13 of the passageway 11, it will close the passageway 11 to prevent the escape of high-pressure air therefrom and the air pressure in passageways 11 and 27 will tend to be the same as the pressure of the source of high-pressure air. It is an important feature of this invention that a small amount of air escapes from the passageway 27 about the pin 26 at the end thereof adjacent the retaining ring 28, since this will tend to prevent the accumulation of any foreign bodies on the pin 26 which might prevent it from moving freely in passageway 27. This is particularly important where the control handle is to be used in conjunction with abrasive blasting equipment, since the environment of the control handle in such application will tend to be laden with fine particles of the abrasive which could collect on the pin 26 and prevent the free movement thereof in passageway 27.

When the force applied to the end 18 of the lever arm 15 is released, the air pressure in passageways 11 and 27 and the spring 21 will cause the lever arm 15 and safety button 25 to return to the positions shown in FIG. 1. The air passing through the passageway 11 from the source at 12 to the atmosphere at 13 will result in a small air pressure within the passageway 27. As men-.

tioned above, such air pressure within the passageway 27 will exert a small force on the enlarged head 25a of pin 26 causing it to automatically return to the position shown in FIG. 3 when the lever arm returns to the position shown in FIG. 1. The gasket 29, if used, should allow the escape of air about the head 25a, at least in the position thereof shown in FIG. 3, in order to prevent the accumulation of foreign bodies thereon as discussed above in connection with the other end of pin 26. The enlarged head 25a not only limits movement of the pin 26 in one axial direction in passageway 27 but also insures that the force exerted on the pin 26 by the air pressure in the passageway 27 will be unbalanced in such a way as to cause the head 25a of pin 26 to project from the body 10.

Finally, the enlarged head 25a provides a large peripheral surface for engagement by the flange on the lever arm 15 and insures adequate strength to resist any amount of force applied to lever arm 15. It will be understood that a spring means, not shown, might be used to urge the pin 26 to move in the axial direction within passageway 27, which would cause the head 25a thereof to project from body 10. However, this has been found to be unnecessary in the embodiment shown and described above.

Referring to FIG. 5, a unit of air actuated abrasive blasting equipment with which the control handle of this invention may be used to particular advantage is shown. Such unit comprises a container 30 in which a supply of abrasive material is sealed. An outlet valve 31 at the bottom of the container 30 is adapted to feed the abrasive material from the container 30 into a mixing chamber 32 under operating conditions. Both the container 30 and the mixing chamber 32 are connected to one side ofa normally closed air actuated inlet valve 33 by

appropriate pipes

34 and 35.. A source of highpressure air (now shown) is connected to the other side of the inlet valve 33 at coupling 36. A portion of the high-pressure air supplied to inlet valve 33 at coupling 34 is conducted to the air actuation chamber 37 ofinlet valve 33 by means of control pipe 38.

A normally open air actuated vent valve 40 is connected to container 30 by an appropriate pipe 41. The outlet 42 of vent valve 40 communicates with the atmosphere in order to exhaust the air pressure in the container 30 when the unit is not in operation. A control pipe 43 conducts air from the air actuation chamber 37 of inlet valve 33 to the air actuation chamber 44 of the vent valve 40.

A remote control air hose 45 is also connected to the air actuation chamber 44 of the vent valve 40 and conducts air to the passageway 11 of the body 10 of the control handle, according to the invention as shown in FIG. 6. A blasting hose 46 is connected to the mixing chamber 32 to conduct the abrasive laden highpressure air to a desired remote point of utilization.

Referring to FIG. 6, the blasting hose 46 may be provided with an appropriate blasting nozzle 47 for manipulation by the operator. The control handle of this invention is preferably mounted on the blasting hose 46 adjacent the nozzle 47 or by means of mounting bands 48 encirclingthe hose 46 and base plate 19 of the con,- trol handle so that the end portion 18 of the lever arm 15 is readily accessible to the operator while he is manipulating the nozzle 47.

It will be understood that high-pressure air from the source will continuously escape to the atmosphere through control pipes 38 and 43, control hose 45 and passageway 11 in the body 10 of the control handle, preventing actuation of normally closed inlet valve 33 and normally open vent valve 40. Thus, unless the control handle is manually operated, no high-pressure air will be supplied to container 30 or mixing chamber 32 through

pipes

34 and 35. In order to activate the unit, the operator pushes in button 25 and applies manual force to the end 18 of the lever arm 15 causing the sealing means 14 to plug the end 13 of passageway 11 in the body 10 of the control handle. This causes the air pressure in the passageway 11, control hose 45 and

actuation chambers

37 and 44 to approach the air pressure supplied thereto from the source of high-pressure air through control pipes 38 and 43. The increase in air pressure in

actuation chambers

37 and 44 opens inlet valve 33 and closes vent valve 40, thereby pressurizing container 30 and passing high-pressure air from the source through pipe 34 and mixing chamber 32 so that abrasive laden high-pressure air is expelled from nozzle 47 through hose 46. The release of the manual force on the lever arm 15 of the control handle by the operator, either intentionally or due to disability, will immediately release the air pressure in actuating

chambers

37 and 44, deactivating the unit.

An alternative control system is shown in FIGS. 7 and 8. In this system the functions of the control pipe 38 and control hose 45 are combined. Thus, referring to FIG. 7, the control pipe 38 of FIG. is replaced by two

sections

45a and 45b of control hose, and the control hose 45 of FIG. 5 is replaced by a plug 50 closing the outlet of the actuation chamber 44 of vent valve 40. Referring to FIG. 8, a three port T junction coupling body 51 is mounted on the base plate 19 of the control handle and one port thereof is connected to the passageway 11 in the body 10 of the control handle. One control hose section 45a is connected between the source of high-pressure air and a second port of the coupling body 51 and the other control hose section 45b is connected between the third port of the coupling body 51 and the actuating chamber 37 of the inlet valve 33. As in the system shown in FIGS. 5 and 6, air from the high-pressure source (not shown) will be vented from the control system to the atmosphere through the passageway 11 in body 10 which is connected to the first port of the coupling body 51 until the lever arm 15 of the control handle is movably operated to plug the passageway 11 through the body 10 thereof, at which time the control system will be pressurized and the unit actuated.

It will be seen that, even if the nozzle 47 shown in FIGS. 6 and 8 were placed on a supporting surface in inverted position from that shown, the control handle could not be inadvertently actuated even by the weight of the hose 46 and nozzle 47, since the safety button 25 would prevent movement of the lever arm 15. It has been found that the lever arm may be subjected to sufficient force under this or similar inadvertent conditions to bend or distort the lever arm 15 without actuating the equipment. On the other hand, once the safety button 25 is pushed in, the control handle may be manually actuated repeatedly or for extended periods of time with very little operator'fatigue.

Finally, it has been found that the control handle of this invention is failure proof under all operating conditions since there are no valve elements to stick or malfunction and all moving parts of the control handle are continuously exposed to moving air streams which prevent theaccumulation of foreign bodies thereon. It is believed that persons skilled in the art will find the various embodiments of this invention to be applicable to a wide variety of equipments which utilize highpressure air in their operation.

What is claimed is:

l. A handle for the remote control of air actuated equipment comprising:

a. a solid body forming a first passageway through said body and a second passageway transverse to said first passageway;

b. means for connecting high-pressure air to one end of said first passageway;

c. a lever arm movably mounted on said body and including a sealing portion adapted to be moved by said lever arm into sealing engagement with the other end of said first passageway;

d. spring means urging said lever arm toward a position in which said sealing portion of said lever arm is out of sealing engagement with said other end of said first passageway;

e. pin means received in said second passageway;

f. said pin means being axially movable between a first position in which a portion of said pin means projects to a given distance from said body and a second position in which said portion of said pin means does not project to said given distance from said body;

g. said pin means, said lever arm and said first passageway being arranged with respect to each other such that said sealing portion of said lever arm cannot be moved into sealing engagement with said other end of said first passageway when said pin means is in said first position; and

h. means urging said pin means toward said first position.

2. A handle for the remote control of air actuated equipment as claimed in claim 1 wherein said second passageway intersects said first passageway.

3. A handle for the remote control of air actuated equipment as claimed in claim 2 wherein said pin means has an enlarged head at one end thereof and retaining means at the other end thereof whereby the movement of said pin means in said second passageway is limited to movement between said first position and said second position thereof.

4. A handle for the remote control of air actuated equipment as claimed in claim 3 wherein said second passageway and said pin means extend through said body with said enlarged head and said retaining means on opposite sides of said body.

5. A handle for the remote control of air actuated equipment as claimed in claim 4 wherein said means urging said pin means toward said second position thereof is air pressure present in said first and second passageways and said pin means and second passageway are dimensioned to allow the restricted escape of air from said second passageway.

6. A handle for the remote control of air actuated equipment as claimed in claim 3 wherein said lever arm is pivotally mounted on said solid body adjacent said sealing portion thereof and said lever arm is adapted to engage the periphery of said enlarged head of said pin means when said pin means is in said first position thereof and the free end surface of said enlarged head when said pin means is in said second position thereof.

7. A handle for the remote control of air actuated equipment as claimed in claim 1 wherein said means urging said pin means toward said second position thereof is air pressure present in said second passageway.

8. A handle for the remote control of air actuated equipment as claimed in claim 1 wherein said means for connecting high pressure air to one end of said first passageway formed by said solid body comprises a coupling body forming a three port passageway therethrough, means connecting one of said three ports of said passageway formed by said coupling body to said one end of said first passageway formed by said solid body and means for connecting high pressure air to another of said three ports of said passageway formed by said coupling body.

9. A handle for the remote control of air actuated equipment comprising:

a. a solid body forming a first passageway through said body and a second passageway;

b. means for connecting high pressure air to said first passageway;

c. a lever arm mounted on said body for movement between a first position and a second position and including means for altering air pressure in said first passageway only when said lever arm is in said first position;

d. means urging said lever arm toward said second position thereof;

e. pin means received in said second passageway and being movable in said second passageway between a first position in which a'portion of said pin means projects to a given distance from said body and a second position in which said portion of said pin means does not project to said given distance from said body;

- 10 f. said pin means, said lever arm and said first passageway being arranged with respect to each other such that said lever arm cannot be moved from said second position to said first position thereof when said pin means is in said first position thereof; and

g. means urging said pin means toward said first position thereof. 10. A handle for the remote control of air actuated equipment as claimed in claim 9 wherein said second 10 passageway intersects said first passageway and said means urging said pin means toward said first position thereof is the air pressure present in said first and second passageways.

Claims

1. A handle for the remote control of air actuated equipment comprising: a. a solid body forming a first passageway through said body and a second passageway transverse to said first passageway; b. means for connecting high-pressure air to one end of said first passageway; c. a lever arm movably mounted on said body and including a sealing portion adapted to be moved by said lever arm into sealing engagement with the other end of said first passageway; d. spring means urging said lever arm toward a position in which said sealing portion of said lever arm is out of sealing engagement with said other end of said first passageway; e. pin means received in said second passageway; f. said pin means being axially movable between a first position in which a portion of said pin means projects to a given distance from said body and a second position in which said portion of said pin means does not project to said given distance from said body; g. said pin means, said lever arm and said first passageway being arranged with respect to each other such that said sealing portion of said lever arm cannot be moved into sealing engagement with said other end of said first passageway when said pin means is in said first position; and h. means urging said pin means toward said first position.

9. A handle for the remote control of air actuated equipment comprising: a. a solid body forming a first passageway through said body and a second passageway; b. means for connecting high pressure air to said first passageway; c. a lever arm mounted on said body for movement between a first position and a second position and including means for altering air pressure in said first passageway only when said lever arm is in said first position; d. means urging said lever arm toward said seCond position thereof; e. pin means received in said second passageway and being movable in said second passageway between a first position in which a portion of said pin means projects to a given distance from said body and a second position in which said portion of said pin means does not project to said given distance from said body; f. said pin means, said lever arm and said first passageway being arranged with respect to each other such that said lever arm cannot be moved from said second position to said first position thereof when said pin means is in said first position thereof; and g. means urging said pin means toward said first position thereof.

10. A handle for the remote control of air actuated equipment as claimed in claim 9 wherein said second passageway intersects said first passageway and said means urging said pin means toward said first position thereof is the air pressure present in said first and second passageways.