Anti-backlash means for adjusting enlargers

Claim 2

A rack and gear drive, comprising: a. an essentially planar carrier frame including opposed side margins, a pair of adjacent parallel disposed rack elements, and yieldable elements integrally connecting each rack element to a corresponding side margin to permit limited movement of each rack element in a direction essentially perpendicular to the carrier frame; b. a supporting means receiving the side margins of the carrier frame for longitudinal movement of the rack elements; c. a drive shaft carried by the supporting means; d. and gear means carried by the shaft for engagement with the rack elements.

Claim 3

A rack and gear drive, comprising: a. an essentially planar carrier frame including opposed side margins, a pair of adjacent parallel disposed rack elements, and yieldable elements integrally connecting each rack element to a corresponding side margin to permit limited movement of each rack element in a direction essentially perpendicular to the carrier frame; b. a supporting means receiving the side margins of the carrier frame for longitudinal movement of the rack elements; c. a drive shaft carried by the supporting means; d. a gear means carried by the shaft for engagement with the rack elements; e. the carrier frame further including adjacent its side margins a pair of tracks; and f. a pair of wheels having an effective diameter corresponding to the pitch diameter of the gear means, rotatable on the tracks to maintain a predetermined spacing between the axis of the shaft and the rack elements.

Claim 4

A rack and gear drive, comprising: a. an essentially planar carrier frame including opposed side margins, a pair of adjacent parallel disposed rack elements, and yieldable elements integrally connecting each rack element to a corresponding side margin to permit limited movement of each rack element in a direction essentially perpendicular to the carrier frame; b. a supporting means receiving the side margins of the carrier frame for longitudinal movement of the rack elements; c. a drive shaft carried by the supporting means; d. a gear means carried by the shaft for engagement with the rack elements; e. the carrier frame further including adjacent its side margins a pair of tracks; and f. a pair of wheels having an effective diameter corresponding to the pitch diameter of the gear means, rotatable on the tracks to maintain a predetermined spacing between the axis of the shaft and the rack elements.

Claim 5

An anti-backlash means, comprising: a. a supporting means having opposed guide flanges; b. a carrier frame defining a plane and including side margins fitting the guide flanges for longitudinal movement relative to the supporting means; c. a pair of rack elements disposed longitudinally in the central region of the carrier frame and a plurality of yieldable elements connecting each rack element to a corresponding side of the carrier frame to permit limited displacement with respect to the plane defined by the carrier frame; d. a drive shaft disposed over the carrier frame in transverse relation thereto; e. a gear having portions forming a pair of drive gear elements mounted on the shaft and engagable with the racks; f. one pair of said elements having teeth offset a preselected amount and arranged, when yieldably pressed between the teeth of said other pair of elements, to compensate for backlash; g. a pair of tracks disposed longitudinally at opposite sides of the carrier frame; h. and a pair of wheels carried by the shaft, the wheels having a diameter corresponding to the pitch diameter of the gear elements to limit intermeshing of the gear and rack elements.

Claim 6

An anti-backlash means, comprising: a. a supporting means having opposed guide flanges; b. a carrier frame defining a plane and including side margins fitting the guide flanges for longitudinal movement relative to the supporting means; c. a pair of rack elements disposed longitudinally in the central region of the carrier frame and a plurality of yieldable elements connecting each rack element to a corresponding side of the carrier frame to permit limited displacement with respect to the plane defined by the carrier frame; d. a drive shaft disposed over the carrier frame in transverse relation thereto; e. a gear having portions forming a pair of drive gear elements mounted on the shaft and engagable with the racks; f. one pair of said elements having teeth offset a preselected amount and arranged, when yieldably pressed between the teeth of said other pair of elements, to compensate for backlash; g. a pair of tracks disposed longitudinally at opposite sides of the carrier frame; h. and a pair of wheels carried by the shaft, the wheels having a diameter corresponding to the pitch diameter of the gear elements to limit intermeshing of the gear and rack elements.

Claim 7

An anti-backlash means as defined in claim 3, wherein: a. the teeth of said rack elements are offset.

Claim 8

An anti-backlash means as defined in claim 3, wherein: a. the teeth of said gear elements are offset.

Claim 9

An anti-backlash means as defined in claim 3, wherein: a. the supporting means is a channel member having side flanges disposed laterally outward from the guide flanges, the side flanges having means for journalling the shaft.