GB2034889A - Printing head for recording apparatus - Google Patents

Abstract

A recording head for a multipoint recorder, the head comprising a bearer bar 2 which is rotated continuously or intermittently, a carriage 1 movable along and about the bar 2, a rotary drum 9 bearing a plurality of printing styluses 10, the drum being intermittently rotated by a Geneva cross member 7 secured to the drum 9 and driven by pins 6 on an interengaging gear wheel 4 rotatable with the bar 2, and means for causing the drum to be intermittently displaced away from its printing position, said means including a cam member carried by a gear wheel 15 which is rotated via the gear wheel 4 and a drum carrying housing 12 pivotally mounted relative to the carriage and having an abutment which is engaged intermittently by rotation of the cam member to effect said drum displacement. <IMAGE>

Description

SPECIFICATION Recording head for chart recorder This invention relates to a recording head for a multipoint recorder, and comprises a bearer bar which when fitted in the recorder is driven continuously or intermittently about its longitudinal axis; a carriage translationally and rotationally movable on the bar; a rotary drum bearing a plurality or printing styluses spaced around its periphery; means for intermittently rotating said drum including a Geneva cross member secured for rotation with the drum and driven by an interengaging gear wheel rotatable with the, and slidable along, bearer bar; and means for causing the drum to be intermittently displaced away from its printing position, said displacement means including a cam member rotatable with a second gear wheel meshing with the first mentioned gear wheel, and a housing pivotally mounted relative to the carriage and carrying said drum, said housing having an abutment which is engaged intermittently by rotation of the cam member to effect said drum displacement.

An embodiment of the invention will now be described by way of example only with reference to the accompanying drawings, in which: Figure 1 is a view from below of a recording head according to the invention, Figure2 is a part sectional view of the head of Figure 1, Figure 3 is a view of enmeshing gear wheels of the head of Figure 1, Figure 4 is a view of the housing carrying the printing drum and Geneva cross drive of the drum, Figure 5 is a section along the V-V of Figure 4,and Figures 6 and 7 show diagrammaticaily upper and lower positions respectively of the recording head.

Referring to Figure 1, the recording head comprises a carriage 1 translationally and rotationally movable on a bearer bar 2 which in use is supported by a chassis (not shown) of a graphic strip chart recorder. Bar 2 carries at one end a gear wheel 3 driven in use by an electrical motor and an interconnected transmission of the recorder. Inside the carriage 1, a gear wheel 4 is secured for rotation with the bar 2, by means of a spline 5. Gear wheel 4 bears two laterally extending pins 6 diametrical opposite to each other and arranged to alternatively and intermittently drive a Geneva cross member 7. The Geneva cross member 7 is rigidly connected to one end of an axle 8 (Figure 5) the other end of the axle having clamped thereon a printing drum 9 bearing different styluses or points 10 impregnated with ink.Axle 8 rotates in a bearing 11 fixed in a housing 12 in which drum 9 is rotatabiy mounted. Housing 12 comprises a bearing 13 surrounding bar 2 and able to pivot freely within a housing 1 4. Gear wheel 4 meshes with a gear wheel 1 5 mounted in the housing 14.

On the face of gear wheel 1 5 adjacent to the Geneva cross member 7, there is provided a cam member comprising two diametrically opposed cam lobes. Cam lobes 1 6 are arranged for cooperating with an abutment 17 formed by an extension of the wall of housing 12 and lying in the path of cam lobes 1 6.

The operation of the recording head described above is the following: The recording head is arranged above the path of the strip chart which is continuously moved, and the head may be laterally displaced along bar 2 by an endless cable (not shown) to which the carriage 1 is connected. When the carriage has arrived at a desired position across the chart, it is lowered by pivoting around bar 2 for momentarily applying one of the ink points 10 on the strip chart, and then raised for movement to the next position. This operation is repeated. The intermittent rotation of drum 9 bearing the ink points 10 is affected by the rotation of bar 2 driving the gear wheel 4 which by means of pins 6 drives the Geneva cross member 7 rigidly connected to drum 9. The two pins 6 allow advancement of the Geneva cross member at each half revolution of the bar 2.Simultaneouslv with each rotational movement of the Geneva cross member 7, one of the cams 16 during its rotation (along the arrow in fig. 3) lifts the housing 12 by abutting against the rim of the abutment 17 and thereafter causes lowering of housing 12 when the rim of the abutment 1 7a falls behind the extremity 1 6a of cam 1 6.

Figure 6 shows the housing 12 and drum 9 raised above strip chart 1 8 by the action of one of the cam lobes 16. During a further 90 rotation of the cam member (Figure 7), the housing 12 and drum 9 pivots under gravity about bar 2 and relative to housing 1 4 which does not pivot. In so doing one of ink points 10 contacts the strip chart 1 8 to mark it. The next cam lobe then raises the housing 12 and drum 9 to permit the recording head to be moved to another lateral position along bar 2 and hence the strip chart, ready for the next marking operation.

Rotation of bar 2 is continuous but may be intermittent.

The number of pins and cam lobes may be one or more than two.

1. A recording head for a multipoint recorder, the head comprising a bearer bar which when fitted in the recorder is driven continuously or intermittently about its longitudinal axis; a carriage translationally and rotationally movable on the bar: a rotary drum bearing a plurality of printing styluses spaced around its periphery; means for intermittently rotating said drum, including a Geneva cross member secured for rotation with the drum and driven by an interengaging gear wheel rotatable with the, and slideable along, bearer bar; and means for causing the drum to be intermittently displaced away from its printing position, said displacement means including a cam member rotatable with a second gear wheel

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

Claims (2)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Recording head for chart recorder This invention relates to a recording head for a multipoint recorder, and comprises a bearer bar which when fitted in the recorder is driven continuously or intermittently about its longitudinal axis; a carriage translationally and rotationally movable on the bar; a rotary drum bearing a plurality or printing styluses spaced around its periphery; means for intermittently rotating said drum including a Geneva cross member secured for rotation with the drum and driven by an interengaging gear wheel rotatable with the, and slidable along, bearer bar; and means for causing the drum to be intermittently displaced away from its printing position, said displacement means including a cam member rotatable with a second gear wheel meshing with the first mentioned gear wheel, and a housing pivotally mounted relative to the carriage and carrying said drum, said housing having an abutment which is engaged intermittently by rotation of the cam member to effect said drum displacement. An embodiment of the invention will now be described by way of example only with reference to the accompanying drawings, in which: Figure 1 is a view from below of a recording head according to the invention, Figure2 is a part sectional view of the head of Figure 1, Figure 3 is a view of enmeshing gear wheels of the head of Figure 1, Figure 4 is a view of the housing carrying the printing drum and Geneva cross drive of the drum, Figure 5 is a section along the V-V of Figure 4,and Figures 6 and 7 show diagrammaticaily upper and lower positions respectively of the recording head. Referring to Figure 1, the recording head comprises a carriage 1 translationally and rotationally movable on a bearer bar 2 which in use is supported by a chassis (not shown) of a graphic strip chart recorder. Bar 2 carries at one end a gear wheel 3 driven in use by an electrical motor and an interconnected transmission of the recorder. Inside the carriage 1, a gear wheel 4 is secured for rotation with the bar 2, by means of a spline 5. Gear wheel 4 bears two laterally extending pins 6 diametrical opposite to each other and arranged to alternatively and intermittently drive a Geneva cross member 7. The Geneva cross member 7 is rigidly connected to one end of an axle 8 (Figure 5) the other end of the axle having clamped thereon a printing drum 9 bearing different styluses or points 10 impregnated with ink.Axle 8 rotates in a bearing 11 fixed in a housing 12 in which drum 9 is rotatabiy mounted. Housing 12 comprises a bearing 13 surrounding bar 2 and able to pivot freely within a housing 1 4. Gear wheel 4 meshes with a gear wheel 1 5 mounted in the housing 14. On the face of gear wheel 1 5 adjacent to the Geneva cross member 7, there is provided a cam member comprising two diametrically opposed cam lobes. Cam lobes 1 6 are arranged for cooperating with an abutment 17 formed by an extension of the wall of housing 12 and lying in the path of cam lobes 1 6. The operation of the recording head described above is the following: The recording head is arranged above the path of the strip chart which is continuously moved, and the head may be laterally displaced along bar 2 by an endless cable (not shown) to which the carriage 1 is connected. When the carriage has arrived at a desired position across the chart, it is lowered by pivoting around bar 2 for momentarily applying one of the ink points 10 on the strip chart, and then raised for movement to the next position. This operation is repeated. The intermittent rotation of drum 9 bearing the ink points 10 is affected by the rotation of bar 2 driving the gear wheel 4 which by means of pins 6 drives the Geneva cross member 7 rigidly connected to drum 9. The two pins 6 allow advancement of the Geneva cross member at each half revolution of the bar 2.Simultaneouslv with each rotational movement of the Geneva cross member 7, one of the cams 16 during its rotation (along the arrow in fig. 3) lifts the housing 12 by abutting against the rim of the abutment 17 and thereafter causes lowering of housing 12 when the rim of the abutment 1 7a falls behind the extremity 1 6a of cam 1 6. Figure 6 shows the housing 12 and drum 9 raised above strip chart 1 8 by the action of one of the cam lobes 16. During a further 90 rotation of the cam member (Figure 7), the housing 12 and drum 9 pivots under gravity about bar 2 and relative to housing 1 4 which does not pivot. In so doing one of ink points 10 contacts the strip chart 1 8 to mark it. The next cam lobe then raises the housing 12 and drum 9 to permit the recording head to be moved to another lateral position along bar 2 and hence the strip chart, ready for the next marking operation. Rotation of bar 2 is continuous but may be intermittent. The number of pins and cam lobes may be one or more than two. CLAIMS

1. A recording head for a multipoint recorder, the head comprising a bearer bar which when fitted in the recorder is driven continuously or intermittently about its longitudinal axis; a carriage translationally and rotationally movable on the bar: a rotary drum bearing a plurality of printing styluses spaced around its periphery; means for intermittently rotating said drum, including a Geneva cross member secured for rotation with the drum and driven by an interengaging gear wheel rotatable with the, and slideable along, bearer bar; and means for causing the drum to be intermittently displaced away from its printing position, said displacement means including a cam member rotatable with a second gear wheel meshing with the first mentioned gear wheel, and a housing pivotally mounted reiative to the carriage and carrying said drum, said housing having an abutment which is engaged intermittently by rotation of the cam member to effect said drum displacement.

2. The recording head of claim 1, wherein the first mentioned gear wheel includes two diametrically opposed pins for engaging the Geneva cross member and wherein the cam member includes two diametrically opposed cam lobes for engaging the abutment.