US2749742A

US2749742A - Pneumatic gauging device

Info

Publication number: US2749742A
Application number: US336346A
Authority: US
Inventors: Aller Willis Fay
Original assignee: Sheffield Corp
Current assignee: Sheffield Corp
Priority date: 1953-02-11
Filing date: 1953-02-11
Publication date: 1956-06-12
Anticipated expiration: 1973-06-12
Also published as: FR1095705A; BE526267A; GB753021A; DE976479C

Description

June 12, 1956 ALLER 2,749,742

PNEUMATIC GAUGING DEVICE Filed Feb. 11. 1953 2 Sheets-Sheet 1 IN V EN TOR.

gj z Maw June 12, 1956 w. F. ALLER PNEUMATIC GAUGING DEVICE 2 Sheets-Sheet 2 Filed Feb. 11, 1953 INVENTOR. K 5. w

United States Patent PNEUMATIC GAUGING DEVICE Willis Fay Aller, Dayton, Ohio, assignor to The Sheitield Corporation, Dayton, Ohio, a corporation of Ohio Application February 11, 1953, Serial No. 336,346

18 Claims. (Cl. 7337.9)

This invention relates to gauging devices for measuring or comparing dimensions.

One object of this invention is the provision of a gauging device of the type having a vertically disposed flow tube provided with a float that is movable along the tube in accordance with the rate of flow and wherein the tube ponent is carried by sheet metal side casing members rising from the base, thus avoiding the utilization of expensive cast housing structures.

Another object is the provision of a gauging device embodying a base member on which the lower component is mounted, the upper and lower components being supported by a casing consituted of sheet metal members having end flanges and tied together at their upper ends by means of the upper component.

Another object is the provision of a gauging device of the character mentioned having a hinged cover member or lid which normally conceals and protects the upper portion of the device and its adjustment means and which can be readily opened to permit inspection or adjustments.

Another object is the provision of a gauging device of the character mentioned in which a relief valve is provided in the upper component and arranged for control by an adjustment means which projects upwardly and which is normally covered and protected by the hinged cover.

Another object is the provision of a gauging device in which the upper end of the vertical tube is held by a tube cap which is slidable in the direction of the tube in the upper component under the control of an adjusting knob, which tube cap includes an air relief valve for relieving air from the upper end of the tube, the air relief valve adjustment means and the adjusting knob being coaxially mounted in the upper component.

Another object is the provision of a gauging device having a plurality of flow tubes arranged closely adjacent one another and a corresponding plurality of pressure regulators arranged compactly at diflerent heights and so staggered as to minimize the width of the casing in which they are enclosed.

I Other objects and advantages of the invention will be apparent from the following description, the appended claims, and the accompanying drawings, in which:

Figure l is a vertical central section of a gauging device embodying the present invention taken on line 11 of Figure 2;

poses of illustration a pair has been shown.

Figure 2 is a horizontal section taken on line 22 of Figure 3 Figure 3 is a rear view of the gauging device with a part of the casing thereof broken away;

Figure 4 is a perspective front view of the gauging device showing it connected to a work gauging element;- and Figure 5 is a detail of a portion of the section of Figure 1.

The gauging device of the present invention is an improvement over existing devices of the type wherein a vertically disposed flow measuring tube having a tapered inner passage and a float element thereinis connected at its lower end to a source of fluid under controlled pressure and at its upper end to a gauge head of any suitable character having a leakage orifice the flow through which is controlled by the size or other characteristic of the object being gauged.

Referring more particularly to the drawings in which the same reference numerals are applied to like parts in the several views the gauging device embodies a housing structure in which a tube 11 is vertically mounted. The tube has a passage therethrough which is tapered so that it is slightly larger at its upper end than at its lower end. A gravity operated float element 12 is carried therein, the vertical position of which is determined by the rate of flow through the tube. The lower end of the tube is supplied with fluid such as air under controlled pressure, and the upper end of the tube communicates through conduit means with a connection 14 on the forward face of the gauging device. This connection 14 is adapted for connection to a flexible tube 15 leading to a work engaging element 16. In the example shown the work engaging element 16 is adapted for measuring the internal diameter of a hole and has suitable orifice openings 17 diametrically spaced thereon (only one of which shows in Figure 4). The orifice outlets 17 communicate through the gauging head with the flexible tube 15. The displacement of the orifice outlets from the surface of the workpiece being gauged will determine the leakage flow through the orifices and will correspondingly vary the rate of flow through the vertically disposed tube 11 depending upon the dimension of the workpiece.

Figure 4 discloses a gauging device which has a single vertically disposed tube 11 therein. The other figures of the drawings illustrate a gauging device which has a plurality of tubes therein. The gauging device can include any number of such tubes; however, for the pur- The following portion of the descriptionwill accordingly be particularly directed to a single tube and its associated structure, the organization being substantially the same for each of the measuring tubes.

The gauging device has a base member 18 which is supporting rubber bumpers 20 at its corners. Bolted adjacent the forward edge of the base member 18 is a lower tube supporting component 21. A manifold 22 is also mounted on the base member 18 at the rear portion of its upper surface. Side panels 23, formed on sheet metal stampings, have inwardly turned flanges 25 around their upper and longitudinal edges. The lower portion of the forward inwardly turned flanges 25 of the panels 23 are fastened by bolts 26 to the forward face of the lower tube supporting component 21. These side panels extend vertically above the base member 18 and have inwardly cupped portions 27 at their upper ends formed by the continuous flanges. An upper tube supporting component 28 is fastened between the side panels adjacent their upper ends and to their forward flanged portions by bolts 30. The side panels 23 have further flanges turned inwardly at 31. The inwardly turned portions 31 extend longitudinally of the side panels 23 only between the lower and upper tube supporting components. At the rear of the gauging device the side panels 23 have. further inwardly turned portions 32. These further inwardly turned portions 32. are interrupted adjacent. the upper end of the panels to allow the fastening of across member.

34 between the side panels by bolts 35. A back panel member 36 also has inwardly turned flanges 37. This back panel member 36 is inserted between the side panels 23. It is bolted at its lower end to manifold member 22 by bolts 38 and at its upper end to cross member 34 by bolts 40. Removal of the back panel 36 by Withdrawing bolts 38 and. 40 opens the interior of the casing structure for adjustments or repairs. The width of the manifold 22 is less than that of theback panel 36 and it and the regulators 63, 63' can be. removed (by suitably twisting the regulatorsv or their supporting pipes). as a unit through the'back panel opening.

The flow tube 11 seats in a resilient washer 41 in a depression in the upper surface of the lower tube supporting component 21. The upper tube supporting tube componet 28 has a vertically slidable tube cap 42. mounted therein. This tube cap 42 has a resilient washer 44 in its lower face into which the vertical tube 11 is seated at its upper end. This tube cap 42 can be tightened downwardly for clamping the flow tube 11 between the rubber washers 41 and 44' by an adjustment member 45 which is inserted into the upper tube supporting component 28 and seats at 46 against the upper end of the tube cap 42. This adjustment member 45 has a knurled adjusting knob 47 at its upper end and a cylindrical hole therethrough.

A covcr or lid 4.8 is supported on the cross member 34 by a hinge fastened to the cross member by bolts 51. This lid 48 extends up and over the upper edges of the side panel 23 and down the forward face thereof. It extends laterally over the flanges of the side panels 23 and terminates shortly below the upper end of the flow tube 11 at the forward face of the device. Bumpers 49 are provided between the lid and the side panel flanges.

A scale 52 bearing calibrations along the flow tube 11 is supported at its lower end on the lower tube supporting component 21 and is located there by locating pins 54. At its upper end the lateral edges of the scale 52 are supported from the side panels. by spacer elements 55 fastened between bolts 56.

Adjustable pointers

58 and 58 are slidable along the scale 52. and are preferably positioned at the upper and lower tolerance limits for any particular gauging operation.

Air under pressure is supplied to the gauging device through a connection 60, a shutoff cock 61 and through the manifold 22. From the manifold 22 air passes through a vertically disposed pipe 62 (the following structure would be duplicated for each of the individual flow tubes and its associated conduits). A regulator 63 is supported by this pipe 62 and controls the pressure of the air supplied to the flow tube. The regulator adjustment means extend out through the back panel 36. From the regulator 63 air passes through flexible conduit 64' and through a connection to the lower tube supporting component. Air then flows through passage 65, float stabilizer 66 and up to the flow tube 11. Air passes in through radial holes in the body of the float stabilizer 66 and up through it to the tube 11 in the modification shown. It has been found thatsuch a unit stabilizes float action and it is believed that this may be caused by the somewhat restricted flow through the stabilizer 66. The stabilizer could take other forms and its function could be accomplished by an axial passage through such a unit. From the flow tube 11 air passes through conduit 68, passages 69 and 70. in the lower tube supporting componentand to the aforementioned connection. 14 from whence it passes to a suitable gauging head where its flow is controlled by the dimension of the workpiece being measured. A bypass connection between the passagcs and 70 in the lower tube supporting componet is provided at 73. This bypass passage 73 is controlled by an adjustable element 74 which is accessible from the forward surface of the lower tube supporting component 21. This adjustable bypass is provided to adjust the amplification factor of the gauging device. It is used to compensate for wear on any particular work gauging element and is. also used to provide different ampiilication factors for the same or different work gauging elements since the tolerances between jobs may vary substantially. in changing the amplification factor of the gauging device i-twould also be necessary, of course, to employ a scale with a corresponding range. The use of this amplification factor adjustment is set forth in more detail in Aller Patent No. 2,593,957, issued April 22, 1952.

A relief channel is provided at 75 in the upper tube cap 42 and air passes through this channel 75 and out at 76 in the upper tube supporting component 28. The flow through this relief channel 75 is regulated by a valve means indicated at 77. This valve means is threaded into the tube cap 42, is biased upwardly by a spring 78, and has a knurled adjusting knob 80 at its upper end.

The adjustments for the tube cap 42 and for the relief valve means 77 are accessible only upon raising the lid 48.

An annular groove 82 which also forms a portion of the upper relief passage cooperates with a projection 84 on a member 85 screwed into the upper tube supporting tube component 28 to limit the axial adjustment of the tube cap 42. The adjustable valve means '77 which controls the relief flow at the upper end of the tube 11 permits more or less of the air flowing to the flow tube 11 to be relieved to atmosphere instead of returning down through the. flexible tube 68 and out through the gauging nozzle. Thus this adjustment 8% can be used to adjust the float position and preserve the amplification in cooperation with the amplification adjustment factor previously referred to. This adjustment is also described in more detail in the aforementioned Patent No. 2,593,957.

In gauging devices embodying the features of the present invention which include a plurality of tubes the flow tubes are located closely adjacent in the device. In order to make the gauging device as compact widthwise as is possible, the regulators are arranged at varying levels above the manifold 22 on their supporting pipes 62. This allows the regulators to overlap horizontally as is shown more clearly in Figure 2.

It is thus seen that a gauging device has been provided which isrelatively simple and. rugged in configuration and which involves primarily sheet metal components which can be fashioned cheaply and which are conveniently assembled. The arrangement of the lid or cover member in association with the other housing members protect,

the inner elements from dirt, dust and the like. It also serves to inhibit the promiscuous tampering with the inner adjustment means they would otherwise be subject to if located onthe face of the device. However, all adjustment means are conveniently accessible when proper adjustments are necessary. A reliable clamping means has been provided for the vertical flow tube. inner components and particularly the tube itself of the gauging device are readily reached for adjustment, re placement or repair.

While the form of apparatus herein described constitute a preferredembodiment of the invention, it is not limited to this precise form of apparatus, and that changes may be made therein without departing from the scope of the invention which-is defined in the appended. claims.

What is claimedis:

1. A gauging device comprising a vertically disposed.

The

lower tube supporting component having seating means for the lower end of said tube, said supporting means having a bottom portion forming a base and providing the sole support for the gauging device, vertically disposed rigid sheet metal side panels, means detachably fixing said panels adjacent their lower ends to said lower tube supporting component with their lower edges engaging the upper surface of the base forming portion of the supporting means, an upper tube supporting component extending between and fixed to each of the side panels adjacent their upper ends and having a seating means for the upper end of the flow tube, said upper tube supporting component being supported entirely by said sheet metal side panels, passages in said lower and upper components communicating with the respective tube ends, means communicating with the lower component passage for connection to a source of fluid under pressure, means communicating with said upper component passage for connection to a controlled leakage means, said flow tube having means oper able therein to indicate the rate of flow through the tube.

2. A gauging device as set forth in claim 1 having a lid member, a hinge supporting said lid member between the side panels and adjacent their upper ends at the rear of the gauging device, said lid extending over the upper ends of the side panels and bridging the space therebetween, and a removable back panel extending between said side panels at the rear of the gauging device.

3. A gauging device as set forth in claim 1 wherein the means communicating with the lower component passage includes a pressure regulator and a vertically disposed pipe element, communicating with said regulator and supporting it from and above the supporting means.

4. A gauging device comprising a supporting means including a lower tube supporting component, said supporting means having a bottom portion forming a base and providing the sole support for the gauging device, relative spaced channel shaped sheet metal side panels fixed to said supporting means and extending upwardly therefrom, said side panels having flanges that project toward one another, an upper component extending between and secured rigidly to each of said side panels adjacent the upper ends thereof, said upper component being supported entirely by said sheet metal side panels, a vertically disposed transparent flow tube carried between said upper and lower components, a lid member, hinge means supporting said lid member from said side panels at the rear of the gauging device, said lid extending over the upper ends of the side panels and down to a level adjacent the upper end of the flow tube, means communicating with the lower tube end for connection to a source of fluid under pressure, means communicating with the upper tube end for connection to a controlled leakage means, said flow tube having means operable therein to indicate the rate of fiow through the tube.

5. A gauging device comprising a supporting means including a lower tube supporting component, said supporting means having a bottom portion forming a base and providing the sole support for the gauging device, channel shaped sheet metal side panels detachably fixed to said supporting means, extending upwardly above said supporting means and enclosing the lateral portions of the lower component, said side panels having inwardly projected flanges along their vertical and upper edges, an upper component extending between and secured rigidly to each of said side panels adjacent the upper ends thereof, a vertically disposed transparent flow tube carried between said upper and lower components, a lid member, hinge means supporting said lid member from said side panels at the rear of the gauging device along a line displaced downward from the upper ends thereof, said lid extending upward and over the upper ends of the side panels and down the forward face of the gauging device to a level adjacent the upper end of the flow tube, and extending widthwise over only a portion of the inwardly projected flanges, means communicating with the lower tube end for connection to a source of fluid under pressure, means com municative with the upper tube end for connection to a controlled leakage means, said flow tube having means operable therein to indicate the rate of flow through the tube.

6. A gauging device comprising a supporting means including a lower tube supporting component, said supporting means having a bottom portion forming a base and providing the sole support for the gauging device, sheet metal side panels fixed to and extending upwardly from said supporting means, an upper component secured rigidly to each of said side panels adjacent the upper ends thereof, a plurality of vertically disposed transparent flow tubes carried between said upper and lower components, individual means communicating with each of the upper tube ends for connection to a controlled leakage means, fluid pressure supply means communicating with the lower tube ends, said fluid pressure supply means comprising a manifold carried by the supporting means and having means for connection to a source of fluid under pressure, and, for each of the flow tubes, a pressure regulator supported above and communicating with said manifold by a pipe means, the regulators being carried at different levels and overlapped horizontally for compactness, a connection from each regulator to the respective lower tube end, each of said flow tubes having means operable therein to indicate the rate of flow through the tube.

7. A gauging device comprising a supporting means including a lower tube supporting component, said supporting means having a bottom portion forming a base and providing the sole support for the gauging device, vertical side panels detachably fixed to said lower tube supporting component and extending upwardly from opposite sides of said supporting means, an upper tube supporting unit fixed to and extending between said side panels. at their upper ends and disposed over the lower component, a vertically disposed transparent flow tube, seating means for the upper surface of the lower end of said tube in the lower component and between the side panels, a tube cap vertically adjustable in said upper unit, seating means for the upper end of said tube in the lower surface of said tube cap, passages in said lower component and said tube cap communicating with the respective tubeends, means communicating with said lower component passage for connection to a source of fluid under pressure, a connection means, a connection from the tube cap passage to said connection means, said flow tube having means. operable therein to indicate the rate of flow through the tube.

8. A gauging device comprising a supporting means in-- cluding a lower tube supporting component, said support ing means having a bottom portion forming a base and providing the sole support for the gauging device, vertical side panels fixed to said lower component, disposed later ally on said supporting means, and extending upward therefrom, an upper tube supporting unit fixed to and supported between said side panels at the upper ends thereof and disposed over said lower component, a transparent vertical flow tube, seating means for the lower end of said tube in said lower component between said side panels, a. tube cap carried for up and down movement in said upper unit, adjustable means engaging said tube cap and threaded into said upper unit, seating means for the upper end of said tube in said tube cap, passages in said lower componeat and said tube cap communicating with the respective tube ends including a relief passage leading from the upper tube end to atmosphere, means communicating with said lower component passage for connection to a source of fluid under pressure, means communicating with the tube cap passage adapted for connection to a gauge head, ad-- justment means threaded into said tube cap for controlling said relief passage, said flow tube having means operable therein to indicate the rate of flow through the tube.

9. A gauging device comprising a supporting means in-- cluding a lower tube supporting component, said supporting means having a bottom portion forming a base and providing the sole support for the gauging device, vertical side panels fixed to said supporting means, disposed laterally thereof, and extending vertically therefrom, an upper tube supporting unit supported between said side panels at the upper ends thereof and disposed over said lower component, a transparent vertical flow tube, seating means for the lower end of said tube in said lower component between said side panels, a tube cap vertically slidable in said upper unit, adjustable clamp means engaging said tube cap and threaded into said upper unit, seating means for the upper end of said tube in said tube cap, passages in said lower component and said tube cap communicating with the respective tube ends, means communicating with said lower block component passage for connection to a source of fluid under pressure, a connection means, a connection from the tube cap passage to said connect-ion means, said flow tube having means operable therein to indicate the rate of flow through the tube, a relief connection to said upper block component passage means, and adjustable means threaded into said tube cap coaxially with said adjustable clamp means for controlling said relief connection.

10. A gauging device comprising a supporting base member forming the sole support for the gauging device, a lower block component mounted on said base member, vertically disposed side panels supported by said lower block component extending upwardly from said base memher and having inwardly extending flanges along their upper and vertical sides, an upper tube supporting unit supported adjacent the upper end of said side panels and therebetween, a transparent flow tube vertically mounted between said lower component and said upper unit and between said side panels, passages in said lower component and said upper unit communicating with the respective tube ends, means communicating with said lower component passage for connection to a source of fluid under pressure, an adjustable relief valve means in said upper unit in communication with said upper passage, a back panel between said side panels, a lid, means hingedly supporting said lid adjacent the upper end of said side panels and at the rear thereof, said lid extending laterally over the inwardly turned flanges of the side panels and extending from the hinge over the upper ends of the side panels and down the forward faces of their flanges to a point below said upper unit, whereby said adjustable means is readily accessible by an upward movement of the aforementioned lid.

II. A gauging device comprising a supporting means including a lower tube supporting component, said supporting means having a bottom portion forming a base and A providing the sole support for the gauging device, vertically disposed side panels supported adjacent the lateral edges of said supporting means, an upper tube supporting unit disposed generally above said lower component and fixed to and extending between the side panels, a vertically disposed transparent flow tube carried between said lower component and said upper unit and horizontally disposed between said side panels, a calibrated plate vertically situated along and extending behind and to each side of said flow tube, locating pins in the upper surface of said lower component for locating the lower edge of siad calibrated plate, the upper end of the plate terminating below said upper unit, and means extending from said side panels adjacent their upper ends detachably flxing the upper end of said calibrated plate to both of the side panels.

12. A gauging device having a vertically disposed flow tube, upper and lower tube supporting components between which the fiow tube is carried, sheet metal side panels extending vertically between said upper and lower components and fixed thereto, said panels having inwardly directed flanges along their vertical edges at the forward face of the gauging device substantially at right angles to the panel sides and forming the forward housing for the device, the flow tube being visible between said flanges,

a calibrated plate supported to the rear of and along said flow tube, said side panels having further flange portions inwardly turned and extending toward said calibrated plate at each side of the flow tube and cooperating with the plate to frame the flow tube while protecting the in terior of the device, means communicating with the lower tube end for connection to a source of fluid under pressure, means communicating with the upper tube end for connection to a controlled leakage means, said flow tube having means operable therein to indicate the rate of flow through the tube.

13. A gauging device comprising a vertically disposed flow tube, a base member, a lower tube supporting component on said base member adjacent the forward edge thereof, flanged side panels secured to said lower component and extending upward from said base member, an upper tube supporting component between said side panels, a manifold having means for connection to a source of fluid pressure and to the lower tube end supported on said base member adjacent the rear edge thereof, a lid member, a detachable back panel between said side panels, the interior of the gauging device being accessible by removal of the back panel, said manifold having a width which is less than that of the back panel whereby it is removable through the back panel opening.

14. A gauging device comprising a transparent flow tube, upper and lower flow tube supporting components, vertical side panels extending along said supporting com ponents to form side housing members, seating means in said lower tube supporting component for the lower end of said tube, a tube cap carried for vertical movement in the upper tube supporting component, passages in said lower tube supporting component and said tube cap communicating with the respective tube ends, adjustable clamping means engaging the tube cap and threaded into the upper tube supporting component for adjustably clamping said tube between said lower tube supporting component seating means and said tube cap, a relief connection in said tube cap communicating with the tube cap passage and leading to atmosphere, adjustable means for said relief connection threaded into said tube cap, the threaded sections being relatively coaxial and the adjustable relief means extending above the adjustable clamping means.

15. A gauging device comprising a transparent flow tube, upper and lower tube supporting components, side panels vertically disposed between upper and lower tube supporting components, seating means in said lower tube supporting component for the lower end of said tube, a tube cap mounted for vertical sliding in said upper tube supporting component, passages in said lower tube supporting component and said tube cap communicating with the respective tube ends, adjustable clamping means engaging the tube cap and threaded into said upper tube supporting component for adjustably clamping said tube between said lower tube supporting component seating means and said tube cap, a relief connection in said tube cap communicating with the tube cap passage, an adjustable means for said relief connection threaded into said tube cap, the threaded sections being relatively coaxial and the adjustable means for said relief extending above the adjustable clamping means, a back panel disposed be tween said side panels, a lid, said lid being hinged to said side panels at the rear of the gauge device, said lid extending over said side panels and down the forward face of the gauging device to a limited extent, whereby the adjustable means are readily accessible by raising the lid.

16. A gauging device comprising a base member forming the sole support for the gauging device and, a lower block component fixed to said base, vertical side panels disposed at the lateral edges of said base, extending upwardly therefrom, and mounted on said lower block component, an upper tube supporting component, a transparent flow tube, said flow tube being vertically supported between said components and horizontally disposed between said side panels, passages in said lower and upper components communicating with the respective tube ends, means communicating with said lower component passage for supplying fiuid under pressure thereto, a connection means accessible from the forward face of the lower component, an outlet connection from said upper component passage, passing through the lower component to said connections means, a bypass connection in the lower component between the outlet connection and the lower component passage, means accessible from the forward face of the lower component for controlling the bypass connection, an adjustable relief valve means in said upper component communicating with the upper component passage means, a back panel between said side panels, a lid, hinge means supporting said lid from said side panels at the rear of the gauging device, said lid extencl ing over the upper ends of the side panels, and down their forward faces to a point below the upper component.

17. A gauging device comprising a vertically disposed transparent flow tube having an indicating float movable therealong, upper and lower tube supporting components, means carrying said components in relatively spaced relationship, one above the other, seating means in the lower component for one end of said tube, seating means for the upper end of the flow tube, adjustable tube clamping means for moving said upper seating means into engagement with the upper tube end, said tube clamping means being threaded into the upper tube supporting component for rotation about a vertical axis and having an adjustment knob, passage means communicating with the upper and lower tube ends through the respective seating means adapted for placing the lower tube end in communication with a source of air under controlled pressure and the upper tube end in communication with a gauging head and including a relief passage leading to atmosphere from the upper tube end, adjustment means for said relief passage threaded coaxially to said adjustable clamping means and having an adjustment knob coaxial to the adjustment knob for said tube clamping means.

18. A gauging device comprising a vertically disposed transparent flow tube having an indicating float movable therealong, upper and lower tube supporting components, means carrying said components in relatively spaced relationship, one above the other, seating means in the lower component for the lower end of the tube, a vertically movable tube cap providing seating means for the upper end of the flow tube, an annular tube clamp threaded into said upper component for adjusting said tube cap and moving said upper seating means into engagement with the flow tube and including an adjustment knob portion, passage means communicating with the flow tube through the lower seating means adapted for connection to a source of air under controlled pressure, said tube cap having passage means communicating with the upper end of the tube through the upper seating means adapted for connection to a gage head and including a relief passage leading to atmosphere, adjustment means for controlling said relief passage threaded vertically in in said tube cap coaxially within said tube clamp and including an adjustment knob portion coaxial to and above the clamp adjustment knob, and a hinged lid normally extending over said knob portions and moveable to clear the knob portions for ready adjustment.

References Cited in the file of this patent UNITED STATES PATENTS 2,593,957 Aller Apr. 22, 1952 2,609,691 Kirwan Sept. 9, 1952 2,643,546 Boehm June 30, 1953 FOREIGN PATENTS 600,402 Great Britain Apr. 8, 1948