GB1582053A - Carriage assembly - Google Patents

Description

PATENT SPECIFICATION

( 11) 1 582 053 Application No 22775/79 ( 22) Filed 23 May 1977 ( 19) Divided out of No 1 582 082 Convention Application No 692 484 ( 32) Filed 3 June 1976 in United States of America (US)

Complete Specification published 31 Dec 1980

INT CL 3 B 41 J 19/00 Index at acceptance B 6 F JG ( 54) CARRIAGE ASSEMBLY ( 71) We, CENTRONICS DATA COMPUTER CORPORATION, a corporation organized and existing under the laws of the State of Delaware, United States of America, and having its principal place of business at 1, Wall Street, Hudson, New Hampshire 03051, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:-

The present invention relates to a carriage assembly for print head assemblies and the like.

According to the present invention there is provided a carriage assembly for print head assemblies and the like comprising upper and lower guideways for slidably receiving associated first and second elongated guide members, one of which comprises a rod, to enable said carriage assembly to reciprocate between end points along a predetermined linear path, cam means including a hollow eccentric cam positioned within the guideway receiving said rod whereby said rod slidably extends through said hollow cam, said cam being rotatable about its longitudinal axis relative to said carriage assembly and said rod for adjusting the position of said carriage assembly relative to said rod, said carriage assembly being movable in a direction transverse to the longitudinal axis of said rod, the carriage assembly additionally comprising a print head assembly mounted thereon and a platen arranged parallel to said rod whereby adjustment of said cam means positions the printing elements of the print head assembly a predetermined distance relative to said platen.

An object of the invention is to provide a novel means for simply and rapidly adjusting the carriage assembly and print head relative to the printer platen.

The above as well as other objects of the invention will become apparent when reading the accompanying description and drawings in which:Figures la, lb and lc are left-hand, front and right-hand perspective views respectively of a carriage assembly designed in accordance with the principles of the present invention.

Figures 2 and 2 a show a side and front elevational views of the print head adjustment cam provided in the carriage assembly of 55 Figures la-lc.

Considering Figures la-lc, there is shown therein only those portions of a printer 10 which are considered to be sufficient for purposes of satisfactorily explaining the 60 present invention.

The structure is shown as being comprised of a channel having a substantially vertically aligned spanning frame member 11 bent at 1 la to form a left-side frame member 12 65 and bent at 1 lb to form a right-side frame member 13 secured to its right-hand end.

A substantially U-shaped bracket 14 is securely fastened to side frame member 13 and further has secured thereto a mounting plate 70 which supports a speed reducing assembly 16 which is coupled with motor 17, said assembly 16 being bolted to plate 15 by fastening means 16 b The forward end of the motor shaft 17 c is provided with a small 75 light-weight fan blade assembly 18 utilized for cooling portions of a printer which typically generate heat during operation, such as the printer electronics, not shown for purposes of simplicity, and the motor 17 80 during operation The output shaft 17 d of motor 17 extends into the case of the speed reducing assembly 16 which is provided with its own output shaft 16 a journalled within a pair of bearings 17 a and 17 b secured to the 85 opposite interior walls of U-shaped support bracket 14 Bearing 17 a is concealed behind bracket 14 but is substantially identical to bearing 17 b Also mounted upon the shaft 16 a so as to rotate therewith is a metal pulley 19 90 having a crowned peripheral surface and further provided with a continuous annular groove 19 a for receiving the resilient 0-ring provided to assure positive drive between drive pulley 19 and a closed loop metallic, 95 tape-like belt, a portion of which has been broken away in Figure lc to expose groove 19 a and 0-ring 20.

The side frame members 12 and 13 have secured thereto elongated upper and lower 100 m it O l ( 21) ( 62) ( 31) ( 33) ( 44) ( 51) ( 52) 1,582,053 shafts 29 and 30 respectively, which are arranged in spaced parallel fashion relative to one another and are adapted to slidably support a reciprocating carriage assembly 31.

The carriage assembly 31 is provided with an opening 31 a and slot 31 b respectively adapted to slidably receive shafts 29 and 30.

Opening 31 a and slot 31 b are provided with journalled bearings (not shown) which slide upon the guide bars or shafts 29, 30 during horizontal motion of the carriage assembly 31.

Upper opening 31 a surrounds shaft 29 while slot 31 b is a substantially U-shaped inverted groove cut into the bottom surface 31 k of the carriage assembly 31.

Mounted upon the upper surface of assembly 31 is a print head assembly 32 having a substantially curved rear surface 32 a adapted to receive and threadedly engage a plurality of solenoids S utilized as the means for driving print wires which wires extend from the forward ends of the solenoids S and through the hollow housing of the print head assembly 32 whereby the forward tips extend through the nose 32 b of the print head housing and typically through a jewel bearing for selectively impacting a print ribbon so as to form dot patterns upon a paper document appropriately positioned against the platen P (Figure 2) which is rotatable to perform line feed and paper slewing operations, for example The print head assembly 32 is hollow and is provided with a cover member 32 e for maintaining the print wires within the housing free of dust, dirt or other harmful contaminants.

The solenoids S are each provided with a pair of leads adapted to be connected to power drive circuits which, in turn, are selectively energized to form the vertical dot patterns, five adjacent vertical dot patterns each of a 7-dot height typically being utilized to represent a numeric or alphabetic character, punctuation mark or other symbol as is conventional in printers of the dot matrix type.

The carriage assembly 31 described hereinabove may be utilized for either unidirectional or bidirectional printers wherein movement of the carriage assembly 31 in the direction shown by arrow 49 of Figure lb may constitute a carriage return operation for unidirectional printers or alternatively may be utilized to provide for right-to-left printing in bidirection printers, for example, of the type described in U S Patent No.

3,858,703, issued January 7, 1975, and assiged to the assignee of the present application.

Figure 2 shows the adjustable mounting for carriage assembly 31 which is comprised of an inverted substantially U-shaped opening 31 b formed in the bottom surface 31 k of carriage assembly 31 so as to embrace and slidably engage lower support shaft 30.

The surface of groove or opening 31 b is provided with a suitable lining 39 which acts as a low friction bearing for shaft 30.

The upper end of the carriage assembly 31 is provided with an opening for receiving the eccentric cam insert 87 having a surrounding 70 cam ring 88 secured thereto by set screw 89.

One surface of the cam ring 88 abuts against the left-hand surface of carriage assembly 31 as shown in Figure lb.

A locking adjustment handle 90 is pro 75 vided with a threaded portion 90 b which threadedly engages a tapped opening 88 a in cam ring 88 The cam insert 87 extends through the opening provided in carriage assembly 31 and may, for example, be pro 80 vided with a flange 87 a along its right-hand edge (see Figure 2 a) so that the flange 87 a and the cam ring 88 cooperatively function to prevent the cam insert 87 from moving relative to the carriage assembly 31 85 The top surface of carriage assembly 31 adjacent to cam ring 88 is provided with a curved convex portion 31 g (see Figures 2 and 2 a) which serves to cooperate with a shoulder a of adjustment handle 90 to lock cam ring 90 88 and hence the cam insert 87 into the desired angular position for adjustment of the print head assembly 32 relative to the platen P in a manner to be more fully described 95 The front end or nose 32 b of the print head assembly 32 may be made adjustable relative to the platen P to compensate for the thickness of the paper document, the number of copies to be made during printing, 100 ete.

By rotating the handle 90 so as to move counter-clockwise as shown by arrow A,, the cam ring 88 rotates in the same direction, as does the cam insert 87, being locked to cam 105 ring 88 by set screw 89 Movement in this direction serves not only to move the print head nose 32 b closer to platen P but, when moving closer, also moves the carriage assembly 31 and the print head assembly 32 110 from a slightly diagonally aligned position towards the horizontal position When the appropriate setting between nose 32 b and platen P is selected, adjustable handle 90 is tightened so that its shoulder 90 a firmly 115 engages the curved portion 31 g along the top surface of the carriage assembly 31 and thereby locks the carriage assembly 31 and hence the print head assembly 32 into the appropriate position 120 The inverted U-shaped opening 31 b formed along the underside of carriage assembly 31 serves to permit the carriage assembly 31 to experience some movement in either the upward or downward vertical direction 125 Rotation of handle 90 in the reverse or clockwise direction as shown by arrow A 2, from the position shown in Figure 2, causes the nose 32 b to move away from platen P and thereby increase the spacing there-between 130 1,582,053 This movement is accompanied with slight tilting of the carriage assembly 31 and the print head assembly 32 so that the print head assembly 32 tends to be substantially maintained in radial alignment with the platen P.

Various changes and modifications can be made in the processes and products of this invention without departing from the spirit and the scope thereof The various embodiments set forth herein were presented for the purpose of further illustrating the invention and were not intended as limiting.

Reference is made to our co-pending Patent Application No 21668/177 serial no 1582052, of which this present application isadivisional application.

Claims (4)

WHAT WE CLAIM IS:

1 A carriage assembly for print head assemblies and the like comprising upper and lower guideways for slidably receiving associated first and second elongated guide members, one of which comprises a rod, to enable said carriage assembly to reciprocate between end points along a predetermined linear path, cam means including a hollow eccentric cam positioned within the guideway receiving said rod whereby said rod slidably extends through said hollow cam, said cam being rotatable about its longitudinal axis relative to said carriage assembly and said rod for adjusting the position of said carriage assembly relative to said rod, said carriage assembly being movable in a direction transverse to the longitudinal axis of said rod, the carriage assembly additionally comprising a print head assembly mounted thereon and a platen arranged parallel to said rod whereby adjustment of said cam means positions the printing elements of the print head assembly a predetermined distance relative to said platen.

2 A carriage assembly as claimed in Claim 1, wherein said platen is cylindrical and said cam means is adapted to substantially radially align said print head assembly with said platen when said cam means is adjusted.

3 A carriage assembly as claimed in Claim 1 or Claim 2, further comprising an adjustable handle releasably secured to said cam means and having a shoulder engageable with an adjacent surface portion of said carriage assembly for locking position of said cam means after adjustment thereof.

4 A carriage assembly as claimed in Claim 3, wherein said carriage assembly surface portion has a convex arcuate surface.

A carriage assembly as claimed in Claim 1 for print head assemblies and the like substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

MARKS & CLERK, Chartered Patent Agents, 57-60 Lincolns Inn Fields, London WC 2 A 3 LS.

Agents for the Applicants.

Printed for Her Majesty's Stationery Office by Burgess & Son (Abingdon), Ltd -1980.

Published at The Patent Office, 25 Southampton Buildings, London, WC 2 A l AY, from which copies may be obtained.