GB2333909A

GB2333909A - Control apparatus and connector for refrigeration system

Info

Publication number: GB2333909A
Application number: GB9801672A
Authority: GB
Inventors: Michael Thomas Murphy
Original assignee: MICROM ELECTRONICS Ltd
Current assignee: MICROM ELECTRONICS Ltd
Priority date: 1998-01-28
Filing date: 1998-01-28
Publication date: 1999-08-04
Also published as: GB9801672D0

Abstract

Control apparatus for a refrigeration system comprises a plurality of remote monitoring and/or control devices connected to a common ribbon cable linking the units to a common central control unit such as a microprocessor. The devices electrically connected to the ribbon cable by an idc connector that has contact elements that penetrate insulation of the common ribbon cable to make contact with its conductive wires. The quick connector may provided with a manually operated clamping ring 21 that is rotatable to apply a clamping force to the cable 4 to cause penetration of the cable insulation by the contacts. The common ribbon cable carries both control data and mains supply power for each remote monitoring and/or control device, and has a profile complementary to the profile of the connector. The connector may include a transparent clamp, a fuse, a local processor or a device status indicator.

Description

CONTROL APPARATUS FOR A REFRIGERATION SYSTEM The present invention relates to control apparatus particularly, but not exclusively, to control apparatus for use with a refrigeration system of the type used in supermarkets or other retail outlets to display frozen or chilled produce such as food and drink.

The term "display cabinet" is used hereinafter to refer to any form of refrigerated unit used by, for example, supermarkets or retail outlets to store and/or display food and drink or other produce and includes, for example, a chest freezer, an enclosed or semi-enclosed chilled transparent cabinet in which food is displayed on one or more shelves and which is accessible on one side by supermarket staff, or an upstanding unit having a plurality of vertically spaced shelves to which consumers have self-service access. The display cabinets may have one or more glass door closures.

Such display cabinets require close supervision to ensure that the produce on sale is displayed effectively and efficiently without risk of it perishing before its sellby date. Such supervision is performed by automatic control apparatus comprising a plurality of monitoring and regulating modules that are each independently connectable to the display cabinet and to the mains supply. Examples of the monitoring and regulating modules required for a display cabinet include a defrost heater. temperature probes, regulators and displays, lighting, fans, pressure transducers, liquid solenoid valves, a compressor motor and a drainpan water level detector. These modules operate together to ensure effective refrigeration. However, the resulting wiring loom, electrical termination blocks and fusing can often be complex and renders manufacture, installation and maintenance time consuming and costly.

It is an object of the present invention to obviate or mitigate the aforesaid disadvantages.

According to the present invention there is provided control apparatus for a refrigeration system comprising a plurality of remote monitoring and/or control devices connected to a common cable linking the units to a central control unit, the devices being electrically connected to the common cable by a quick connector that has contact elements that penetrate insulation of the common cable to make contact with its conductive wires, wherein the common cable carries control data and mains supply power for each device.

The quick connector preferably comprises a clamping member that is operable to apply a clamping force to the cable so that the contact elements are forced to penetrate the common cable. There may be provided a pressure element that overlies the cable and is acted on by the clamping member so as to apply said clamping force.

The pressure element may have a transparent viewing port to enable inspection of the cable.

Preferably the quick connector has a support surface that receives the cable, the contact elements projecting from the support surface. The support surface is preferably contoured to complement the shape of the cable.

The quick connector may comprise a housing within which there is provided a fault diagnosis indicator and a port through which an electrical conductor connecting the contact elements to a control device passes. Preferably the contact elements are mounted on a printed circuit board that underlies the support surface, the surface being provided with apertures through which the contacts elements project.

A specific embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a diagrammatic representation of the control apparatus of the present invention; Figure 2 is an exploded perspective view of a quick-connector and common cable of the present invention; Figure 3 is a perspective view of a main body of the quick-connector of figure 3 Figure 4 is a perspective view of the main body of figure 3 with the common cable mounted thereon; Figure 5 is a perspective assembled view of the main body. common cable and a pressure plate of the quick-connector of figure 2; Figure 6 is a perspective view of the quick-connector of figure 5 shown fitted with a clamping ring; Figure 7 is a sectioned side view of an assembled quick-connector and cable of the present invention; Figure 8 is an exploded perspective underneath view of an alternative embodiment of a quick-connector and cable of the present invention; Figure 9 is an exploded perspective view of the quick-connector of figure 8, viewed from above; Figure 10 is a perspective view of a main body of the quick-connector of figures 8and9; Figure 11 is a perspective view of the main body of figure 10 shown with cable fitted; Figure 12 is a perspective part-assembled view of the main body cable and pressure plate of the quick-connector of figure 8; Figure 13 is a perspective view of the fully assembled quick-connector of figure 8; and Figure 14 is an underneath perspective view of the quick-connector assembly of figure 13.

Referring now to the drawings, figure 1 shows diagrammatically an example of the control apparatus for a refrigeration display cabinet (not shown). A principal control node 1 provides a termination interface for all external wiring in the display cabinet. The control node 1 is supplied with mains power by a cable 2 and is connected to a remove monitoring and control unit 3 comprising, for example, a conventional personal computer terminal. The principal node 1 is connected between ends of a common ribbon cable loop 4 that is designed to carry both control data signals and mains power.

At spaced locations along the ribbon cable 4 there are connected subordinate nodes 5 each having a lead 6 that supplies an associated control device 7 with power and control signals derived from the ribbon cable 4. Each subordinate node 5 comprises a quick-connector 8 that clamps on to the common ribbon cable 4 in a snap-fit engagement so that it can receive data from and/or send data to the remote monitoring and control unit 3 via the principal node 1. The control devices 7 may include, for example, temperature and pressure probes and regulators, fans, liquid solenoid or electronic expansion valve controls, energy efficient door and trim heaters (which act to de-mist the glass door and to heat the area of the cabinet around the door so that the customer does not come into contact with the cold surfaces), a defrost controller, lighting, back pressure regulator valve controls, air flow and mass flow monitors, a humidity controller, a compressor motor and a drainpan water level detector. The operation of each of these devices will be understood by the skilled person in the art and is not discussed here.

The principal node 1 provides a compact termination interface for all external wiring required by the display cabinet. The terminations include. for example, incoming mains power to the cabinet, supervisory personal computer communication links, other external control signals and both ends of the common ribbon cable 4.

Figures 2 to 7 show an exemplary embodiment of the quick connector 8 that forms each subordinate node 5. The assembled connector 8 (shown in exploded form in figure 2 and in fully assembled form in figure 6) is generally cylindrical in configuration and comprises a main body 9 having a central contoured platform 10 from which protrude upstanding cable-piercing contact pairs 11, each pair 11 being designed to make contact with a relevant electrically conductive wire within the ribbon cable 4. The platform 10 is contoured to form two elongate grooves 1 0a separated by a rib 10b. One of the grooves 10a, containing three contact pairs 11, is designed to receive that part of the ribbon cable 4 that carries the data signals and the other groove 1 0a receives that part of the ribbon cable 4 that carries the mains conductor. It will be seen that the ribbon cable 4 is contoured in a complementary manner to the platform 10 so as to fit snugly therewith. Flanking the platform 10 are upstanding arcuate walls 12 with strengthening webs 13. The external face 14 of each wall 12 is threaded to receive a clamping ring (described below). The ribbon cable piercing contacts 11 are mounted on a printed circuit board 15 located immediately below the platform 10 and pass through apertures provided in the platform 10. A base plate 16, shown in figure 7 only, closes the underside of the main body 9.

The quick connector 8 also comprises an intermediate pressure plate 17 having a transparent viewing port 18 intersected by spaced transverse depending walls 19 that, in use, make contact with the exposed surface of the ribbon cable 4. Seals 20 are located between the pressure plate 17 and the arcuate walls 12 that flank the platform 10 of the main body 9, so as to prevent the ingress of moisture and dirt. The quick connector 8 is completed by a clamping ring 21 that has an internally threaded depending annular skirt 22 designed to engage with the threads on the arcuate walls 12 of the main body 9. An external surface of the clamping ring 21 is provided with spaced recesses 22 that are designed to facilitate manual grip during rotation of the ring 21. Below the printed circuit board 15 the main body 9 has a radially outward extending port 23 which receives the lead 6 to which the associated control device 7 is connected. Inside the main body 9 between the base plate and the printed circuit board 15 there is provided a fuse 24 and a fault diagnosis L.E.D. 25 that emits pulses of light according to the condition of the connector 6, the control device 7 to which it is connected and the fuse 24. The circuit board 15 may also be fitted with a local processor so that information and data can be stored and processed locally within each quick-connector.

To attach the control devices 7 to the ribbon cable 4, each quick connector 8 is in turn presented to the common ribbon cable 4 at a convenient location. The cable 4 is received between the arcuate walls 12 of the main body 9 and overlies the contacts 11 as shown in figure 4. The seals 20 are then placed in position and the pressure plate 17 is dropped into place over the ribbon cable 4 and between the flanking arcuate walls 12 such that the depending transverse walls 19 of the pressure plate 17 come into contact with the upper surface of the cable 4. Finally the clamping ring 21 is screw-connected to the main body 9 and acts to clamp the pressure plate 17 in place. The clamping force applied by the ring 21 via the pressure plate 17 causes the cable 4 to move downwards so that it rests in the contoured recess of the platform 10 and in so doing its external insulating sleeve is pierced by the contact pairs 11 which then make contact with the internal conductors of the cable 4 as shown in figures 6 and 7.

The control devices 7 receive signals from the controller 3 via the principal node 1 and common ribbon cable 4 which operate under a standard communication protocol. Accurate synchronisation pulses for clock calibration can be sent from the principal node. Each subordinate node 5 has a unique address to ensure that data sent by the controller 3 is directed to the appropriate control device 7. The control signal data and the mains power are transferred from the cable 4 to the control device 7 via the contacts 11, the printed circuit board 15 and the lead 6.

The quick connector 6 arrangement permits installation of the control devices 7 in a quick and easy fashion. The connector 6 (with control device 7 already attached) is simply presented to the cable 4 and, with the cable 4 received on the platform 10, the pressure plate 17 and clamping ring 21 are added and the clamping ring 21 is rotated until the contact pairs 11 penetrate the cable insulation and make contact with the wire. The arrangement is modular so that any number of quickconnectors can be added depending on the particular application. The present invention replaces conventional labour intensive point to point internal refrigerated display cabinet wiring terminations and fusing. The display cabinets are selfcontained and operate independently and if required they can be integrated into a supermarket control and alarm monitoring system.

An alternative embodiment of the quick-connector of the present invention is shown in figures 8 to 14, in which parts corresponding to those of figures 2 to 7 are indicated by the same reference numerals increased by 100 and are not further described except insofar as they differ from their counterparts in figure 2 to 7.

In this alternative embodiment the ribbon cable 104 comprises a comparatively wide section 1 04a and a narrow, thin rib 1 04b that is designed to enable correct orientation of the cable 104 during assembly.

The contact pairs 111 mounted on the printed circuit board 115 project through apertures provided in the platform 110 of the main body 109 such that only pointed tips 11 la of the contacts protrude from the surface of the platform. 110. Each pair is again designed to penetrate the cable insulation and to make electrical contact with the appropriate conductor within the insulation. The main body 109 is provided on its external surface with integral mounting brackets 130 that are apertures to receive the appropriate fixings and a port 123 that differs from its counterpart in the embodiment of figures 2 to 7 in that it extends approximately tangentially from the main body 109.

The transparent pressure plate 117 is substantially disc-shaped and includes a fuse and fuse holder 124. The transparent nature of the pressure plate 117 enables viewing of a fault indication L.E.D. 131 that is mounted on printed circuit board 115 and projects through an aperture 132 in the main body 109.

It will be appreciated that numerous modifications to the above described design may be made without departing from the scope of the invention as defined in the appended claims. For example, the personal computer may be in the form of a touch screen terminal or a hand-held "palm-top" terminal. In addition, appropriate interface software can be used to make the system compatible with other remote monitoring and control devices. It will also be appreciated that the ribbon cable may be replaced by one or more discrete single conductor cables.

Claims

CLAIMS 1. Control apparatus for a refrigeration system comprising a plurality of remote monitoring and/or control devices connected to a common cable linking the units to a common central control unit, the devices being electrically connected to the common cable by a quick connector that has contact elements that penetrate insulation of the common cable to make contact with its conductive wires, wherein the common cable carries control data and mains supply power for each device.
Control apparatus according to claim 1, wherein the quick connector comprises a clamping member that is operable to apply a clamping force to the cable so that the contact elements are forced to penetrate the common cable.
Control apparatus according to claim 2, wherein there is provided a pressure element that overlies the cable and is acted on by the clamping member so as to apply said clamping force.
4. Control apparatus according to claim 3, wherein the pressure element has a transparent viewing port to enable inspection of the cable.
Control apparatus according to any preceding claim, wherein the quick connector has a support surface that receives the cable, the contact elements projecting from the support surface.
6. Control apparatus according to claim 5, wherein the support surface is contoured to complement the shape of the cable.
7. Control apparatus according to any preceding claim, wherein the quick connector comprises a housing within which there is provided a fault diagnosis indicator.
8. Control apparatus according to any preceding claim, wherein the quick connector has a port through which an electrical conductor connecting the contact elements to a control device passes.
9. Control apparatus according to claim 5 or 6, wherein the contact elements are mounted on a printed circuit board that underlies the support surface, the surface being provided with apertures through which the contacts elements project.
10. Control apparatus according to any preceding claim, wherein each quickconnector is fitted with a fuse and fuse carrier.
11. Control apparatus according to any preceding claim, wherein each quickconnector is fitted with a local processor.
12. Control apparatus according to any preceding claim, wherein the quickconnector is provided with a device status indicator.
13. Control apparatus for a refrigeration system substantially as hereinbefore described with reference to the accompanying drawings.