GB2141585A - Pressure switch - Google Patents

Abstract

A pressure switch mounted on a printed circuit board comprises a movable contact 4 operable by a pressure-sensitive diaphragm 7 and a fixed contact 12 adjustable by a ranging screw 6. <IMAGE>

Description

SPECIFICATION Medium to low range, printed circuit board mounted, pressure switch with ranging fa cility.

The device shall comprise of an electrical contact actuated directly by a pressure being applied on a diaphragm, housed in a plastic moulding with integral post type electrical contacts serving as fixing and contact to the circuit board.

1. The electrical contact will comprise of two components i) pressure contact ii) zero spring.

They will be of the slow moving type contact, gold plated or similar depending upon intended duty and life.

2. The electrical circuit will be made by a force being applied to the pressure contact from a diaphragm, as the pressure on the positive side of the diaphragm increases the switch gap closes.

3. The switch point can be adjusted by means of a ranging screw which acts on the zero spring (one half of the contact). By varying the tension on the zero spring, the contact gap can be adjusted giving an effective means of set point switching.

4. The contacts, diaphragm and ranging screw shall be mounted in a two part plastic housing crimped together by the two contact posts on low pressure range and by four contact posts on the higher ranges.

5. Exact ranges will be determined by commercial requirements. The switching point will be adjustable between 0 and 100% of the range. The anticipated ranges will be thus: Low 0-10" wg 0-50" wg 0-100 wg High 0-250 wg To maximum of: 0-150 psi.

A sub minature pressure switch compatible with modern printed circuit board manufacture and assembly techniques comprising of the following novel features: 1. A contact, by virtue of its design, capable of being manufactured to provide a known spring rate. Adjustable during manufacture by section and width of cutouts. See Drawing 005 detail 'A' and 'B'.

2. A pressure switch of subminature dimensions capable of being soldered directly to electrical printed circuit boards.

3. To provide a method of sealing, by clinching both top and bottom mouldings and compressing the anular of the diaphragm, to create a combined seal across both positive and negative chambers.

4. A staked method of construction by driving pins through the lower moulding, into undersize holes in the contact and press-fitting into the top moulding.

5. A pressure switch capable of manufacture with dual-in-line conductor legs suitable for mounting in 0. 1" matrix circuit boards.

6. The ability to transduce a pressure signal directly on a printed circuit board.

7. A method of providing an adjustable switch point setting, by a single screw acting on the zero plate.

CLAIMS (2 Jul 1984) 1. A sub-miniature pressure switch for use with a printed circuit board, comprising a pressure chamber having one wall defined by a flexible diaphragm bearing upon a flexible and resilient moving contact connected to a first conductor leg, and a static contact cooperable with the said moving contact and connected to a second conductor leg, the said moving contact being arranged to flex about a hinge line at least partially defined by at least one elongate cutout in the contact material, the section and width of the said cutout(s) being chosen to impart a desired spring rate to the moving contact.

2. A sub-miniature pressure switch for use with a printed circuit board, comprising a pressure chamber having one wall defined by a flexible diaphragm bearing upon a flexible and resilient moving contact integrally formed with a first conductor leg, and a static contact co-operable with the said moving contact and integrally formed with a second conductor leg, the said moving contact being arranged to flex about a hinge line at least partially defined by at least one elongate cutout in the contact material, the section and width of the said cutout(s) being chosen to impart a desired spring rate to the moving contact.

3. A pressure switch as claimed in claim 1 or 2, in which the diaphragm bears directly upon the moving contact.

4. A pressure switch as claimed in claim 1, 2 or 3, in which the effective position of the static contact is adjustable by means of a setting screw adapted resiliently to deform a portion of the static contact towards the moving contact.

5. A pressure switch as claimed in claim 1, 2, 3 or 4, comprising a two part housing, in which the parts of the housing are crimped together with a periphery of the diaphragm trapped between them.

6. A pressure switch as claimed in claim 5, in which the diaphragm has a marginal bead which is received in a matching recess in one of the housing parts.

7. A pressure switch as claimed in claim 6, in which the marginal bead is annular.

8. A sub miniature pressure switch substantially as hereinbefore described with reference to the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (8)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Medium to low range, printed circuit board mounted, pressure switch with ranging fa cility. The device shall comprise of an electrical contact actuated directly by a pressure being applied on a diaphragm, housed in a plastic moulding with integral post type electrical contacts serving as fixing and contact to the circuit board. 1. The electrical contact will comprise of two components i) pressure contact ii) zero spring. They will be of the slow moving type contact, gold plated or similar depending upon intended duty and life. 2. The electrical circuit will be made by a force being applied to the pressure contact from a diaphragm, as the pressure on the positive side of the diaphragm increases the switch gap closes. 3. The switch point can be adjusted by means of a ranging screw which acts on the zero spring (one half of the contact). By varying the tension on the zero spring, the contact gap can be adjusted giving an effective means of set point switching. 4. The contacts, diaphragm and ranging screw shall be mounted in a two part plastic housing crimped together by the two contact posts on low pressure range and by four contact posts on the higher ranges. 5. Exact ranges will be determined by commercial requirements. The switching point will be adjustable between 0 and 100% of the range. The anticipated ranges will be thus: Low 0-10" wg 0-50" wg 0-100 wg High 0-250 wg To maximum of: 0-150 psi. CLAIMS A sub minature pressure switch compatible with modern printed circuit board manufacture and assembly techniques comprising of the following novel features: 1. A contact, by virtue of its design, capable of being manufactured to provide a known spring rate. Adjustable during manufacture by section and width of cutouts. See Drawing 005 detail 'A' and 'B'. 2. A pressure switch of subminature dimensions capable of being soldered directly to electrical printed circuit boards. 3. To provide a method of sealing, by clinching both top and bottom mouldings and compressing the anular of the diaphragm, to create a combined seal across both positive and negative chambers. 4. A staked method of construction by driving pins through the lower moulding, into undersize holes in the contact and press-fitting into the top moulding. 5. A pressure switch capable of manufacture with dual-in-line conductor legs suitable for mounting in 0. 1" matrix circuit boards. 6. The ability to transduce a pressure signal directly on a printed circuit board. 7. A method of providing an adjustable switch point setting, by a single screw acting on the zero plate. CLAIMS (2 Jul 1984)

1. A sub-miniature pressure switch for use with a printed circuit board, comprising a pressure chamber having one wall defined by a flexible diaphragm bearing upon a flexible and resilient moving contact connected to a first conductor leg, and a static contact cooperable with the said moving contact and connected to a second conductor leg, the said moving contact being arranged to flex about a hinge line at least partially defined by at least one elongate cutout in the contact material, the section and width of the said cutout(s) being chosen to impart a desired spring rate to the moving contact.

2. A sub-miniature pressure switch for use with a printed circuit board, comprising a pressure chamber having one wall defined by a flexible diaphragm bearing upon a flexible and resilient moving contact integrally formed with a first conductor leg, and a static contact co-operable with the said moving contact and integrally formed with a second conductor leg, the said moving contact being arranged to flex about a hinge line at least partially defined by at least one elongate cutout in the contact material, the section and width of the said cutout(s) being chosen to impart a desired spring rate to the moving contact.

3. A pressure switch as claimed in claim 1 or 2, in which the diaphragm bears directly upon the moving contact.

4. A pressure switch as claimed in claim 1, 2 or 3, in which the effective position of the static contact is adjustable by means of a setting screw adapted resiliently to deform a portion of the static contact towards the moving contact.

5. A pressure switch as claimed in claim 1, 2, 3 or 4, comprising a two part housing, in which the parts of the housing are crimped together with a periphery of the diaphragm trapped between them.

6. A pressure switch as claimed in claim 5, in which the diaphragm has a marginal bead which is received in a matching recess in one of the housing parts.

7. A pressure switch as claimed in claim 6, in which the marginal bead is annular.

8. A sub miniature pressure switch substantially as hereinbefore described with reference to the accompanying drawings.