AIRLINE HANDSET FOR TYRE INFLATION APPARATUS

Abstract: An airline handset (10) for use in controlling the flow of compressed air to or from a pneumatic tyre in order to inflate or deflate the tyre, the handset including manually operable valve means (18A, 18G) controlling communication between first and second ports and between the second port and atmosphere, the handset includes display means (24) providing an indication of whether communication between the first and second ports, or between the second port and atmosphere is effected. There is also disclosed a handset including means for restricting flexing of an airline hose so as to minimize the risk of rupture of the hose by an internal coupler.

Description: AIRLINE HANDSET FOR TYRE INFLATION APPARATUS . Technical Field This invention relates to a handset for an airline for use in controlling the flow of compressed air to or from a pneumatic tyre in order to inflate or deflate the tyre. Background Art One common type of handset comprises a die cast aluminium body provided with a trigger operated valve for use in controlling the flow of air through the body. The trigger is arranged such that in a first position, the valve is closed; when squeezed to move the trigger to a second position the valve is operated to permit air to flow through the body from the tyre to be exhausted to the atmosphere to deflate the tyre; and upon further squeezing of the trigger, the valve permits air to flow through the body in order to inflate the tyre. The handset further includes a mechanical analogue pressure gauge arranged to display the pressure of air in the tyre when the valve is in its first position. It has been found that since the pressure gauge only provides an accurate pressure reading when no air is passing through the handset, users tend to be confused by the display of the gauge during inflation or deflation, and has resulted in the over inflation of tyres due to users not realising that the pressure displayed during inflation is not accurate. A further disadvantage with known handsets is that the nature of the connection to the airlines is such that repeated flexing of the airline can result in damage thereto due to the coupler of the airline rupturing the airline. The known handsets are also difficult to calibrate and often require regular re-calibration. Objects of the invention are to minimize the disadvantages associated with the handset described above. Summary of the Invention According to a first aspect of the invention there is provided a handset comprising a first port, a second port, valve means controlling communication between the first and second ports and between the second port and the atmosphere, and display means indicative of whether communication between the first and second ports, or between the second. port and the atmosphere is effected. The display means preferably comprises a liquid crystal display, preferably arranged to display an arrow, preferably a flashing arrow, indicative of communication between the first and second ports, and an oppositely oriented, preferably flashing, arrow indicative of communication between the second poπ and the atmosphere. Each flashing arrow preferably comprises a plurality of parts arranged so that when the arrow is being displayed, the parts of the arrow are displayed so as to form an animated display. Each arrow preferably comprises two parts, the parts being arranged to be displayed alternately when the arrow is displayed. Conveniently, the display means is also arranged to display the pressure at the second port, the display means preferably being arranged to cease displaying the pressure on communication being made between the second port and the first port or the atmosphere. According to a second aspect of the invention there is provided a handset comprising a first port arranged to receive an airline, and means provided adjacent the port to restrict flexing of the airline. The means for restricting flexing preferably comprises a generally cylindrical recess of diameter slightly larger than the external diameter of the airline and of depth at least equal to the length of the part of the coupler which extends within the airline, the first port being provided within the recess. It will be recognised that by restricting flexing of the airline, the risk of damage thereto due to the coupler rupturing the airline is reduced. The handset preferably further comprises a second port arranged to receive a second airline, means for restricting flexing of the airline also being provided adjacent the second port. Brief Description of Drawings The invention will further be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a plan view oi a handset in accordance with an embodiment of the invention; Figure 2 is a cross sectional view along the line X-X in Figure 1; Figure 3 is an enlarged cross-sectional view of part of the handset of Figures 1 and 2; Figure 4 is an end view of the part of Figure 3; Figure 5 is an enlarged cross-sectional view along the line Y-Y in Figure 2; Figure 6 is an enlarged cross-sectional view along the line Z-Z in Figure 5; Figure 7 is a view similar to Figure 2 of an alternative construction; and Figure 8 is an exploded diagrammatic view of the handset of Figure 7. Description of Preferred Embodiments The handset illustrated in the accompanying drawings comprises an integral-skinning polyurethane moulded body 10 including a handle 12 which, as shown in Figure 2, is slightly downwardly curved, the handle 12 being of substantially circular cross-section so that the handle 12 fits comfortably in the users hand. The material of the body 10 is preferably resistant to damage due to the body being scraped or dragged along the ground, in use, the integral-skinning polyurethane tending to bounce when dragged thus reducing damage due to abrasion. The body 10 further includes an integral enlarged hollow head 14. The surface of the head 14 which is intended to be uppermost in use includes two recesses 16 within which are provided depressible buttons 18 for use in the operation of the handset. The buttons 18 are conveniently marked with + and - signs, the + button 18a being used to inflate a tyre, in use, the - button 18b being used to deflate the tyre. The head 14 includes an opening permitting access to the interior thereof, the opening being closed on the front face of the head 14 by a transparent cover 22 beneath which is provided a liquid crystal display (LCD) 24. The cover 22 is recessed into the head 14 and is of dished form in order to reduce the risk of the cover 22 being scratched. In addition, the cover 22 is constructed from a scratch resistant material. The LCD 24 forms part of an assembly which comprises a moulded plastics twin airline connector 26 provided on the lower surface of a support 28 -which also carries a circuit board upon which the LCD 24 is mounted, and a valve mechanism arranged to be operated using the buttons 18. The connector 26 is moulded so as to include two hollow, generally cylindrical projections 30 of internal diameter slightly larger than the external diameter of the airiine hoses to which the handset is connected, in use. One of the projections 30a is arranged to receive a supply line hose arranged to supply compressed air to the handset from a suitable compressor (not shown), the other projection 30 being arranged to receive a distribution line hose for supplying air from the handset to the tyre during inflation thereof, and for carrying air from the tyre to the handset during deflation of the tyre. An inwardly extending integral flange 32 is provided on the inner surface of each of the projections 30, the flanges 32 defining regions of reduced diameter within each of the projections 30. The airlines are each provided with couplers in the form of axially extending, externally screw threaded hollow cylindrical members which when coupled to the handset extend through the regions of reduced diameter, and mate with respective nuts which engage the rear surfaces of the flanges 32 to prevent removal of the airlines from the handset. Commonly, the couplers of airlines extend into the ends of the respective airline hose by a considerable distance. Since the hoses are flexible, there is a tendency for the hoses to be ruptured by the cylindrical members of the couplers when the ends of the hoses are flexed adjacent the coupler. In order to minimize the risk of such rupturing of the hoses in the present construction, the flanges 32 are spaced from the free ends of the projections 30 by an amount greater than the length which the couplers extend within their respective hose. Such an arrangement restricts bending of the end regions of the hoses, and hence reduces the risk of the hoses being ruptured by the couplers. The connector 26 includes a recess 36 with which a tooth 38 provided on the support 28 engages in order to attach the connector 26 thereto. In addition, a bolt 34 is provided to attach the connector 26 to the support 28. In a modification, the recess 36 and tooth 38 may be omitted, the connector 26 being mounted by means of, for example, four bolts. The support 28, as shown in Figure 3, includes first and second recesses 40, 42 which are arranged to define first and second chambers 40a, 42a with the connector 26 when attached thereto, the first chamber 40a communicating with the air supply line, the second chamber 42a communicating with the air distribution line. Respective passages 40h, 42b are provided within the support 28 in order to permit communication between the airlines and the valve mechanism. The end face 48 of the support 28 (Figure 4) is provided with a pair of grooves 52, 54. The groove 52 communicates with the passage 40b, and hence with the first chamber 40a and the supply line, the groove 52 extending from the passage 40b to a point aligned with the + button 18a* The other groove 54 communicates with the distribution line through the passage 42b and extends to a position aligned with the + button 18a and to a position aligned with the - button 18h* The support 28 is further provided with an elongate through bore 44 (shown by -a dashed line in Figure 3) through which an elongate bolt 46 extends, in use, in order to secure the support 28 to the body 10. The valve mechanism comprises a machined metal member 56 (Figures 5 and 6) which includes a pair of passages 40c, 42c each of which is arranged to communicate with one of the grooves 52, 54 provided in the support 28, the member 56 being secured to the end face of the support 28 by means of a pair of bolts 50. It will be recognised that as an alternative to using a machined member 56, the member could be injection moulded so as to include the passages. The member 56 includes a pair of parallel bores aligned with the + and - buttons 18 and communicating with the grooves 52, 54 through passages 4θ£, 42c, a valve stem 58 being slidable in each of the bores. The valve stems 58 each include O-rings 60 arranged to form seals between the valve stems 58 and the walls of their respective bores. The valve stems 58 are movable in their respective bores by the buttons 18 between first and second positions, helical springs 62 being provided in the bores to bias the valve stems 58 to their first positions. As shown in Figures 5 and 6, the O-rings of the valve stem 58 associated with the + button 18a are arranged such that in the first position of the stem 58, one of the O-rings lies between the openings of the passages 40c, 42c, substantially preventing communication therebetween. However, on depressing the + button 18a, the valve stem 58 is moved downwardly as shown in the drawings moving the said O-ring to a position below the passage 40c, permitting communication between the passages 40c, 42c, and the grooves 52, 54, and hence between the air supply and air distribution lines. When the air supply line is connected to a suitable compressor and the air distribution line is connected to a pneumatic tyre, it will be recognised that depression of the + button 18a results in inflation of the tyre. The arrangement associated with the - button 18h differs from that described above in that on depression of the - button 18h, communication is permitted between the groove 54 and a groove 68 extending parallel to the axis of the bore and communicating with atmosphere. It will be recognised therefore that on depressing the - button 18h, air from the tyre is permitted to exhaust to atmosphere resulting in deflation of the tyre. Stops 70 are provided to restrict movement of the buttons 18, and hence to restrict movement of the valve stems 58. As shown in Figure 3, a bore 72 is provided in the support 28 communicating with the recess 42. An high accuracy electronic pressure sensor is provided in the bore 72 in order to monitor the pressure in the chamber 42a, in use. The output of the pressure sensor is processed by means of a suitable circuit on the circuit board of the LCD 24 to permit the detected pressure to be displayed on the LCD 24, the circuit being powered by a power source housed in the head 14, for example, a lithium cell. The circuit is arranged so that the detected pressure may be displayed in a number of different forms, for example in a range of units of measurement, the choice of unit being input by the supplier or owner during setting up of the apparatus using the +/- buttons 18. In addition to being connected to the pressure sensor, the circuit is connected to switches monitoring the buttons 18, for example by monitoring the positions of the valve stems 58. On detecting that one of the buttons 18 has been depressed, the circuit is arranged to cease displaying the detected pressure, and instead to provide an indication as to the communication permitted by the valve mechanism by displaying the appropriate one of the arrows 74, one arrow being displayed to show that communication between the first and second chambers 40a, 42a is permitted, and hence that inflation is occurring, the other arrow 74 being displayed when communication is permitted between the second chamber 42a and atmosphere, hence that deflation is occurring. The arrows 74 are preferably arranged so as to flash as described below, the flashing arrows catching the users attention to indicate that inflation or deflation is occurring, the removal of the display of the measured pressure reducing the risk of the user being confused by the display. As shown in Figure 1, each of the arrows 74 comprises two parts 74a and 74_>. In use, the LCD 24 is controlled so that during inflation or deflation, the two parts 74a, 74b of the appropriate arrow 74 are displayed in an alternating fashion so as to provide an animated effect which may be further emphasized by displaying only part 74a followed by displaying only part 74b, followed by a brief time when neither of the parts 74a, 74b are displayed. Alternatively, the arrows 74 may consist of more than two parts in order to emphasize the animated effect. The LCD 24 is arranged so that each element of the display is arranged to flicker so that whilst certain parts of the display are switched on, other parts are switched off, reducing the total amount of power required to operate the display. By switching between the various parts of the display at high speed, the flicker can be at a sufficient speed so as to be substantially indiscernible to the human eye. It will be recognised that the provision of such a feature results in an increase in the working life of the power source, the source requiring replacement at less frequent intervals. A detector is provided in the first chamber 40a in order to monitor the air pressure therein. The circuit may be arranged so that on the pressure in the first chamber 40a falling to atmospheric pressure as would happen if the handset were removed from the compressor, further operation of the circuit requires a "password" in the form of a sequence of depressions of the + and - buttons 18 to be entered. It will be recognised that such a feature reduces the risk of the handset being stolen as the thief would not be able to operate the handset unless the "password" was known. Where the handset is used in conjunction with a token or coin operated compressor which switches off after a predetermined period of time and may result in the pressure in the first chamber 40a falling, it is desirable for the password to be required only after the pressure in the first chamber 40a has been at atmospheric pressure for a period exceeding a predetermined period of time, for example several hours. Alternatively, the "password" feature may be omitted or may be switched off by the owner of the handset. It is envisaged that rather than measuring the pressure in the first chamber 40a, the pressure may be measured at a port communicating with groove 54, the pressure in the groove being substantially equal in use to that in the first chamber 40a. The circuit is arranged such on connection of the handset to the compressor, connection being sensed by an increase in the pressure in the first chamber 40a, the pressure sensor in the recess 72 is re-calibrated by detecting the pressure in the chamber 42a (which is at atmospheric pressure on connecting the handset to the compressor as the distribution line is not connected to a tyre at that stage), then storing the detected pressure in a memory location of the circuit. During subsequent use of the handset, the pressure readings detected by the sensor are 'corrected' using the stored value of the atmospheric pressure. The detection of connection to a source of pressure can be utilized to close a switch connecting the cell in circuit such that in the absence of connection to a source of pressure the circuit of the handset is not energized. In order to enhance the life of the power source, the circuit is arranged so that if the handset is not used for a period exceeding a predetermined period, output to the LCD 24 is suspended so that the LCD 24 does not display a message, and thus does not draw power from the source, the display 24 becoming operative again on depression of one of the buttons 18. The circuit is also arranged to monitor the power source and provide a visual indication when the source requires changing, for example by displaying the character 76 illustrated in Figure 1. The circuit comprises an electronic device arranged to control the display of the LCD 24, and a programmed processor controlling the operation of the handset. It is envisaged that the circuit would be modified so as to combine the processor with the device for controlling the LCD 24. An alternative is for the circuit to be a dedicated electronic circuit, rather than under the control of a stored program. Figures 7 and 8 illustrate the most recent embodiment of the handset whose basic construction, and mode of operation, is extremely similar to that described above. Reference to Figure 8 indicates that the components within the head 14 are defined by a number of interengaging modules. The LCD 24 is received within an electronics case assembly 101 which also includes the transparent cover 22. The assembly 101 fits within the upper part of the head 14 of the moulded body 10 and thus is exposed in an aperture in the upper face of the head 14. The outer structure of the electronics case assembly is formed from moulded synthetic resin material (preferably a polycarbonate) and the assembly 101 houses the main circuit board including the processor of the handset. Abutting the lower face of the assembly 101 is a moulded synthetic resin (preferably nylon) valve block 102 abutted at its end adjacent the handle 12 by a moulded synthetic resin (preferably acetal) button block 103, air seals being interposed between the blocks 102, 103 as needed. Towards the opposite end of the valve block 102 from the button block 103, and interposed between the valve block 102 and the case assembly 101 is a moulded synthetic resin (preferably nylon) sensor holder 104 which receives and supports the pressure sensor of the airline handset and a filter unit which filters the atmospheric connection to the sensor. The pressure sensor (not shown in the drawings) communicates with a chamber of the valve block 102 which, in use, is exposed to the pressure in the airline connecting the handset to the tyre, there being appropriate electrical connections between the sensor and the p.c.b. in the assembly 101. The hose connector 26 is generally similar to that described in relation to Figures 1 to 6 above, but is formed as a pair of substantially mirror image mouldings (one of which is shown at 105 in Figure 8) and which in use are secured together trapping in place a pair of identical hose connector inserts 106. The hose connector inserts 106 are turned from brass blanks and when the connector 26 is formed around the inserts 106 by assembly of the two mouldings 105 the inserts 106 are held firmly in place against axial and angular movement relative to the mouldings -105. The mouldings can be secured together by adhesive, solvent welding, other forms of welding, or alternatively by transverse screws or bolts. Moreover, the connector 26 is secured to the body 10 by any of the methods described above in relation to Figures 1 to 6. Interposed between the connector 26 and the valve block 102 are first and second adapter elements 107, 108. The shaping of the element 107, 108 differs by virtue of the angles at which the two airline hoses are to leave the handset, but the functions of the elements 107, 108 are identical. Each includes a spigot indicated by the suffix a which is received within a respective passage of the block 102 there being an O-ring seal surrounding each spigot so as to seal each spigot to the block 102 and a filter unit between each spigot and the respective passage in the block 102 to minimise ingress of contaminants. At their opposite ends the elements define unions indicated by the suffix b which are received as a push-fit within the respective hose connector inserts 106, the unions again now being encircled by O-rings which ensure a sealed connection with their respective insert 106. The brass inserts 106 are internally screw-threaded adjacent the regions which receive the unions 107h and 108h, and are also internally screw- threaded at their outermost ends. The preferred method of connecting an airline hose to a hose connector insert 106 is, prior to attaching the airline connector 26 to the body 10, to thread the hose through the interconnected mouldings 105 and the respective insert 106 to project from the face of the connector 26 which will engage the lower surface of the head 14 in use. The projecting part of the or each hose is then fitted, generally by crimping, with an externally screw-threaded adapter and the hose is then pulled back to engage the adapter in the respective connector insert 106. Thereafter the hose and adapter assembly is rotated within the respective insert 106 to mate the external screw-thread of the adapter with the internal screw-thread of the insert 106 to lock the hose to the insert, and thus to the connector 26. The adapter crimped to the or each hose includes a coupler extending within the hose, but the length through which the coupied extends within the hose is chosen to be less than the length of hose within the mouldings 105 of the connector 26 so that the mouldings, as described above, protect the house against the risk of rupture by restricting bending of the hose in the region of the end of the coupler. The internal screw-thread at the outermost end of each insert 106 provides an alternative means of attaching a hose and adapter to the insert. Should it be desired to attach the hose and adapter to an insert 106 without removing the connector 26 from the head 14 then the adapter can be screwed into the outermost end of the respective insert 106 but using this method the protection for the hose afforded by the connector 26 is minimized since the end of the coupler of the adapter, within the hose, may be close to, or even outside, the end of the hollow cylindrical projection of the connector 26 from which the hose extends. The modular assembly method of the embodiment illustrated in Figures 7 and 8 facilitates mass production assembly of the handset, but it is to be understood that the mode of operation of the handset is as described above with reference to Figures 1 to 6. In both of the embodiments the use of an integral-skinning polyurethane body 10 provides the circuitry and the display with a high degree of protection against mechanical shock and rough handling.

Claims: CLAIMS 1. An airline handset comprising a first port (40), a second port (42), valve means controlling communication between the first and second ports and between the second port and atmosphere, and characterized by display means (24) indicative of whether communication between the first and second ports, or between the second port and the atmosphere is effected. 2. A handset as claimed in Claim 1 , characterized in that said display means preferably comprises a liquid crystal display (24). 3. A handset as claimed in Claim 1 or Claim 2, characterized in that said display is arranged to display an arrow, indicative of communication between the first and second ports, and an oppositely oriented, arrow indicative of communication between the second port and the atmosphere. 4. A handset as claimed in any one of Claims 1 to 3, characterized in that said display is intermittent or flashing. 5. A handset as claimed in Claim 4, wherein the display includes a flashing arrow comprising a plurality of parts arranged so that when the arrow is being displayed, the parts of the arrow are displayed so as to form an animated display. 6. A handset as claimed in Claim 5, characterized in that each arrow comprises two parts, the parts being arranged to be displayed alternately when the arrow is displayed. 7. A handset as claimed in any one of Claims 1 to 6, characterized in that said display is also arranged to display the pressure at the second port. 8. A handset as claimed in Claim 7, characterized in that said display is arranged to cease displaying the pressure on communication being made between the second port and the first port or the second port and atmosphere. 9. An airline handset having a first port arranged to receive an airline hose, and means provided adjacent the port to restrict flexing of the airline hose. 10. A handset as claimed in Claim 9, characterized in that said means for restricting flexing comprises a generally cylindrical recess of diameter slightly larger than the external diameter of the airline hose and of depth at least equal to the length of the part of the coupler which extends within the airline hose.

Inventors: BEBBINGTON RICHARD, ROGERS ANDREW PETER, BEBBINGTON, RICHARD, ROGERS, ANDREW, PETER
Applicants: BEBBINGTON RICHARD, GARAGE EQUIP MAINTENANCE, ROGERS ANDREW PETER, BEBBINGTON, RICHARD, GARAGE EQUIPMENT MAINTENANCE CO. LTD., ROGERS, ANDREW, PETER
Application year: 1995
Main classification: B60S5
IPC codes: B60S5, G01L17