US3929081A

US3929081A - Electro mechanical adder mechanism

Info

Publication number: US3929081A
Application number: US543727*A
Authority: US
Inventors: Stanley Joseph Ketterer
Original assignee: Singer Co
Current assignee: Singer Co
Priority date: 1975-01-24
Filing date: 1975-01-24
Publication date: 1975-12-30
Anticipated expiration: 1992-12-30

Abstract

An adder mechanism with a plurality of adder links, each of which contains a thick section and a thin section, each adder link may have a selected section placed in a effective position by a plurality of link actuators individually connected to the adder links. Adder spacers interconnect the adder links at the effective position whereby the total dimension of the adder spacers and the selected thin or thick sections in the effective position may be utilized to influence, for example, stitch forming instrumentalities of a sewing machine. The adder mechanism is supported in a frame which also supports a drive shaft. A plurality of collars, one for each link actuator, is slidably keyed to the drive shaft to rotate therewith. Each collar is formed with at least one tooth, designed to engage with one or the other of a pair of oppositely disposed and axially spaced apart teeth on an internal surface of the link actuator thereby to drive the link actuator and connected adder link with its thin section or its thick section to the effective position adjacent the adder spacer. A solenoid is utilized to alter the position of the collar that a selected one of the spaced apart teeth on the link actuator may be engaged.

Description

United States Patent [1 1 Ketterer Dec. 30, 1975 [54] ELECTRO MECHANICAL ADDER MECHANISM [75] Inventor: Stanley Joseph Ketterer,Jamesburg,

[73] Assignee: The Singer Company, New York,

[22] Filed: Jan. 24, 1975 [21] Appl. No.: 543,727

[52] US. Cl. 112/158 D; 112/158 B; 74/56; 235/61 PA [51] Int. Cl. D05B 3/02 [58] Field of Search 112/158 D, 158 A, 158 B, 112/158 E, 158 R, 157,-121.13, 121.11; 74/56, 568, 569; 235/61 R, 61 PA [56] References Cited UNITED STATES PATENTS 3,812,729 5/1974 Ketterer 112/158 D 3,881,433 5/1975 Davidson 112/158 E Primary Examiner-Werner H. Schroeder Assistant ExaminerPeter Nerbun Attorney, Agent, or FirmRobert E. Smith; Edward L. Bell; Julian Falk [57] ABSTRACT An adder mechanism with a plurality of adder links, each of which contains a thick section and a thin section, each adder link may have a selected section placed in a effective position by a plurality of link actuators individually connected to the adder links. Adder spacers interconnect the adder links at the effective position whereby the total dimension of the adder spacers and the selected thin or thick sections in the effective position may be utilized to influence, for example, stitch forming instrumentalities of a sewing machine. The adder mechanism is supported in a frame which also supports a drive shaft. A plurality of collars, one for each link actuator, is slidably keyed to the drive shaft to rotate therewith. Each collar is formed with at least one tooth, designed to engage with one or the other of a pair of oppositely disposed and axially spaced apart teeth on an internal surface of the link actuator thereby to drive the link actuator and connected adder link with its thin section or its thick section to the effective position adjacent the adder spacer. A solenoid is utilized to alter the position of the collar that a selected one of the spaced apart teeth on the link actuator may be engaged.

4 Claims, 8 Drawing Figures US. Patent Dec. 30, 1975 Sheet 1 of2 3,929,081

US, Patent Dec. 30, 1975 Sheet 2 of2 3,929,081

Ill/I a c 1 .III f2 ELECTRO MECHANICAL ADDER MECHANISM BACKGROUND OF THE INVENTION The invention relates to electromechanical devices capable of translating electrical pattern signals into movements of stitch forming instrumentalities to produce predetermined stitch patterns.

Such an electromechanical device is disclosed in the U.S. Pat. No. 3,812,729, assigned to the same assignee as the instant invention. In the above patent is disclosed a disc adder mechanism having discs keyed to a rotating drive shaft interposed between discs freely journaled on the drive shaft. The freely journaled discs are rotated by frictional contact with the keyed discs but by means advantageously orienting the freely journaled disc with the keyed disc an additive element could selectively be additionally interposed between the disc or removed therefrom in order to obtain a variable output. 1

In this manner a series of paired discs having additive elements varying in binary arithmetiosequence could be mounted on a sewing machine armshaft to produce a variable stitch pattern; and a similar series of paired discs having suitable additive elements could be located in a sewing machine bed to produce a variable feed pattern.

The above device, while adequate, had the drawback of being bulky, and requiring the location of the paired discs in both the sewing machine arm and in the bed. The device was also found to be subject to extraneous excitation due to machine vibration disturbing the friction coupling between the paired discs. Since proper operation was so friction dependant a high loading was required which increased total power consumption. Standardization was also made more difficult in that several different major components, i.e., keyed discs, were required in order to obtain the desired binary arithmetic series for needle position and feed.

SUMMARY OF THE INVENTION The instant invention seeks to retain the advantages of the prior art device in minimizing wear surfaces, in providing adequate signal input and machine response time to prevent missed stitches, and in optimizing the very low ratio of signal power required to total machine power required; while providing the additional advantages of preventing extraneous excitation and reducing the friction requirements so that power consumption may be decreased, in an extremely compact device capable of a high degree of standardization.

These improvements are achieved in a device having a plurality of adder links, each adder link having a thin section and thick section, the adder links capable of having these sections juxtaposed in a binary arithmetic series. Each adder link is connected to a link actuator which is driven to place the adder link in a selected juxtaposed position. Adder spacers interconnect the adder links at an effective position that the total dimensional change of the adder links and the adder spacers may actuate an output member connected to the desired sewing instrumentality.

The link actuator and adder links are supported in a frame which also supports a drive shaft extending through the link actuators. The drive shaft has slidably keyed thereto a plurality of collars, one for each link actuator. Each collar has at least one gear tooth which may be engaged with one or the other of a pair of spaced apart teeth on the link actuator to drive the link actuator in a selected direction, terminating with the selected thin or thick section of the adder link attached to the link actuator adjacent the adder spacer.

The collars are slidably positioned to engage a selected one of the spaced apart teeth of the link actuator by a latching solenoid, which may be programmed by any suitable means such as punched tape or digital integrated logic circuitry for example.

By suitable arrangement, a single frame may support link actuators and adder links for needle position as well as feed, resulting in compact construction. All parts except for the adder links are standardized. Since friction between parts is not required for stability, less power is consumed and the device is no longer subject to extraneous excitation.

DESCRIPTION OF THE DRAWINGS For a better understanding of the invention and the objects and advantages achieved thereby reference may be had to the attached specification and accompanying drawings where:

FIG. 1 is a top plan view of a sewing machine with the top cover and adder frame housing cover plates removed to show details of the mechanism subject of the invention;

FIG. 2 is a cross section taken substantially along the line 22 of FIG. 1 to illustrate the connection of the adder mechanismindicated in FIG. 1 to the feed mechanism of the sewing machine;

FIG. 3 is a view taken substantially along line 33 in FIG. 1 showing link actuator in one of two possible positions;

FIG. 4 is a view taken substantially along line 44 in FIG. 1 showing link actuator in other possible position;

FIG. 5 is a cross section of link actuator taken along line 5''5 of FIG. 3;

FIG. 6 is across section of link actuator taken along line 6-6 of FIG; 3;

FIG. 7 is a cross section of link actuator taken along line 77 in FIG. 3 and showing in addition the driving collar for the link actuator and solenoid for positioning the driving collar, and

FIG. 8 is a schematic of the drive mechanism indicating the approximate timing of the device.

In FIG. 1 is shown a sewing machine 10 having a frame 11 supporting an armshaft 12 driven by a motor via gears 13, 14. A'crank l5 on the end of the armshaft l2 drives a sewing machine thread take up link 16, and, by means of a connecting link 17 a needle bar 18 supported for endwise reciprocation in a needle bar gate 19, pivotably supported on the frame 11 by screw 20. Also apparentfin FIG. 1 are controls 22, 23, 24, 25, and 26 for setting various parameters of sewing machine operation.

An adder mechanism assembly 30 is evident in FIG. 1 with broken away main cover 31 and adder cover 32 that more detail may be apparent. The assembly is supported in an adder frame housing 35 suitably attached to the sewing machine frame 11, and itself supports in bearings 37 a drive shaft 38 having a drive pulley 39 attached at one end which is connected by means of a belt 41 to an armshaft pulley 42 mounted on the armshaft 12. A third pulley 43 and second belt 44 attached to the armshaft 12 transfers power from the armshaft to a feed drive shaft (not shown) for operation of the feed system of the sewing machine. An idler pulley 45 adjustably attached to the adder housing 35 by screw 46 maintains tension on belt 41 (see FIG. 2). The drive pulley 39 is twice the diameter of the armshaft pulley 42 and therefore makes one complete revolution for each two needle bar reciprocations.

Supported on the drive shaft 38 and slidably keyed thereto to rotate therewith but remain axially shiftable are a plurality of driving collars 50 a-f, one for each of a plurality of link actuators 56 a-f which freely encircle the drive shaft (see FIGS. 3 and 4). Each link actuator 56 is fashioned with a pair of fins 63 which project into clearance grooves 64 in the housing 35 and main cover 31, thereby to insure that the link actuator motion is maintained transverse to the drive shaft 38 (see FIG. 7). The driving collars 50 are each slidable on the drive shaft 38 as individually influenced by a forked armature extension 67 (see FIG. 7), extending through openings 65 in the adder housing 35, which extensions are part of armatures 68 pivotably supported on return pole pieces 69 affixed to electromagnets 70, a typical one of which is shown in FIG. 7. A spring 71 maintains the driving collars 50 in the position shown in FIG. 7 when the electromagnets 70 are not energized which corresponds to the position shown in FIG. 1 of driving collar 50d and link actuator 56d. When selected electromagnets 70 are selectively energized by, for example, a punched tape device or a more sophisticated logic memory device, the driving collars 50 connected by the armature extensions 67 to to selected electromagnets 70 are slid along the drive shaft 38 to the position of driving collar 50f into link actuator 56f in FIG. 1 resulting in the relative repositioning of these components to the position shown in FIG. 4 as will be explained below.

The driving collars 50 are formed with a pair of lugs or

teeth

75, 76 axially aligned with each other but separated by 180 (see FIGS. 3, 4 and 7). The link actuators 56 are also formed with lugs or

teeth

80 and 81 which are located opposite each other but are axially spaced from each other (see FIGS. 3, 4, and 6). For the position of the components shown in FIGS. 3 and 7, the driving collar 50d as rotated by the driving shaft 38, drive pulley 39, belt 41, armshaft pulley 42 and armshaft 12 has brought the tooth 75 of the driving collar in contact with the tooth 80 of the link actuator 56d moving the link actuator to that position shown in FIG. 3 where the teeth are driven out of mesh. The link actuator 56 will remain in that position or will constantly be urged to that position by the

teeth

75, 76 of the driving collar 50 meshing with the tooth 80 of the link actuator prior to each reciprocation of the needle bar 18 as will be explained below.

If the electromagnet 70 were to be energized at the position of the components shown in FIGS. 3 and 7, the armature extension 67 will move the driving collar 50 downwardly as viewed in FIG. 7 or towards the viewer as seen in FIG. 3. The tooth 76 of the driving collar 50 will engage with a first ramp surface 85 (see also FIGS. 4 and 6) which will permit the driving collar to axially shift its position in less than 90 of rotation with minimum vibration and noise. Thus tooth 75 of driving collar 50 will have axially shifted from the position shown in FIG. 7, Le, in alignment with tooth 80 oflink actuator 56, to a position in alignment with tooth 81 of the link actuator. Continued rotation of the driving collar 50 will cause tooth 75 of the driving collar 50 to engage with tooth 81 of the link actuator 56, driving the link actuator to the position shown in FIG. 4 relative to the driving collar 50 and shaft 38 until the

teeth

75 and 81 go out of mesh.

If the electromagnet were to be de-energized at the position of the components shown in FIG. 4, the armature 68 and armature extension 67 would be subject to a restoring force due to spring 71 which will urge the driving collar 50 upward as viewed in FIG. 7. A second ramp surface 86 (see FIGS. 3, 4, 5 and 7) will permit the driving collar 50 to axially shift its position in less than 90 of rotation through engagement with the tooth 76 thereby to realign tooth of the driving collar with tooth of the link actuator.

Thus the link actuators 56 may be selectively located in a forward or rear position as required to produce a decorative pattern as will be further described below. The driving collars 50 are formed with a pair of spaced grooves (see FIG. 7) which engage, one or the other, with an internal fin 91 on the link actuator 56 to prevent spurious shifting of the driving collar other than in the manner described above in order to avoid noisy operation or damage to the various components.

Visible in FIG. 1 and also partially in FIGS. 3 and 4, each link actuator 56 has attached thereto a adder link 95 a-f. An upstanding pin 96 (see FIGS. 3 and 4) on the adder link 95 fits into a hole 98 on the link actuator 56, permitting some rotational movement of the adder link while accommodating total reciprocating motion of the link actuator. Each adder link 95 a-f is formed with a thin and a thick section which may be urged by the link actuators 56 a-f into a selected effective position adjacent a plurality of adder spacers 100 slidably carried by the adder housing 35 in slot 101. For example driving collar 50a has been positioned by an energized electromagnet 70a to urge the link actuator 56a and the adder link 95a attached thereto to a rearward position so that a thin section of adder link 95a is adjacent the adder spacer 100. If the electromagnet 70a were de-energized the driving collar 50a would, as described above, reposition the link actuator 56a and the attached adder link 95a to a forwardly position, thereby placing a thick section of the adder link adjacent the adder spacer 100.

The adder links 95a, 95b, 95c and 95d have thin and thick sections sized to produce incremental output approximately according to the common binary 8, 4, 2 and 1 code. Adder spacer is fixed in position in the slot 101 of the adder housing 35 by pin 106. Thus any incremental output produced by adder links 95 a-d is in reference to the fixed adder spacer 105, and in fact produces a bight output for the needle bar 18 as will be explained below.

The needle bar gate 19 is adapted to move the needle bar 18 laterally as urged by a driving arm pivoted thereto (see FIG. 1). An adaptor 111 fastened to the driving arm 110 by screw 112 supports a ball headed stud 115 adjustably in bore 116 by means of set screw 1 17. A bight pivot bracket 120 fastened to adder housing 35 by screws 121 pivotably carries a bight output lever 123. A socket 124 in the bight output lever 123 accommodates the ball headed stud 115. A bight output spacer 125 connects the bight output lever 123 to the first link adder 95a. A spring bias (not shown) on the driving arm 110 urges the bight output lever 123 into continual contact with the bight output spacer 125 and insures intimate contact at all times between adder links 95 a-d and the adder spacers 100 to the fixed adder spacer 105 that selected incremental output of these adder links may betransferred to,the needle bar gate 19 and needle bar 18 carried therein.

The adder links 95e and 95f also produce an output in reference to fixed adder spacer 105 but,- as reference to FIG. 1 will disclose, in the opposite direction to the bight output. The adder links 95e,and 95f produce a feed output as will be explained below, and are capable of four discrete positions as for example full forward feed, full reverse feed and intermediate forward and reverse feed. If more positions are required each additional adder link utilized will double the numberof possible positions with only slight increase in space required. 1 i I The adder links 95e and 95f are connected by adder spacer 100 to join their incremental output and transfer it to a feed output spacer 130. A feed pivot bracket 131 fastened to the adder housing 35 by screws 132 pivotators 56 in the de-energized and energized state respecbly supports on pin 133 afeedoutput crank 135. The

feed output crank 135 has an arm 136 held in contact with'the feed output spacer 130 by a bias spring 140 (see FIG. 2) through linkagejas will be disclosed. A pin 137 fast to the feed output'crank 135 impinges on a feed sliderpin 142 attachedto a feed slider 143. The feed slider 143 is carried freely slidable on a forked end 144 by a shouldered screw 145. The other end 146 of the feed slider 143 also split to accommodate an upper compound lever 150. The feed slider 143 is supported thereon by a pair of pins 151. The upper compound lever 150 is connected to a lower compound lever -2"through an adjustable e'ccentric ISS which enables 'feed output of the adder links to be compensated for operation with a feed system subject to manufacturing variation. A connecting link 158 completes linkage connection to a bell crank 159 secured to a feed regulating shaft 160. The bias spring 140 is connected to the connecting link 158 and serves to maintain a substantially constant bias on the feed output spacer 130 and

adder links

95e and 95f. A separate bias spring (not shown) on the feed regulating shaft 160 maintains the bell crank 159 in contact with stud 161 on the connecting link 158, unless otherwise urged by a manual feed control linkage 165. During manual feed control, the electromagnets 70 are in a deenergized state and the

adder links

95e and 95f may be in a full reverse position to place the connecting link 158 in a further most position to the right, as seen in FIG. 2, so that the stud 161 will not impinge on the bell crank 159 during manual feed. I

The adder links 95a, 95b, 95c and 95? may also be arranged so that with the electromagnets 70 in a deenergized condition the needle bar 18 will be located in center needle position. Thus non-utilization of bight or feed pattern capability will ideally place the machine in the most favorable condition for straight stitching manually controllable feed.

Referring to FIG. 8, the armshaft 12, armshaft pulley 42, belt 41 and drive pulley 39 are indicated schematically along with idler pulley 45. Since the armshaft 12 is directly connected to the needle bar 18 and sewing needle carried thereby, a point on the periphery of the armshaft pulley 42 may be arbitrarily assigned to the position of needle in work material as A. Since the drive pulley 39 rotates at one-half the speed of the armshaft pulley 42, two points Al 180 apart on the periphery of the drive pulley may be assigned the position of the needle in the work material. The position of the components shown in FIGS. 3 and 4 represent the full forward and full reverse positions of the link actuatively of electromagnets 70. In these positions the adder links 95 a-d for needle position have been place with the selected thin or thick section adjacent the adder spacers 100 and the needle bar gate 19 and needle bar 18 carried thereby have completed lateral excursion and are in a selected position. At this time the sewing needle may penetrate the fabric. Concurrently tooth or 76 of driving collars 50 a-d may begin a controlled lateral shift down ramp or 86 of the link actuators 56 as a result in a change in the energization state of electromagnets 70. Wherev the periphery of drive pulley 39 represents increasing time going counter clockwise, points B represents status of components as shown in FIGS. 3 and 4, after which needle penetration, A: may take place.

Lateral shift of the driving collar 50 will occur in less than of collar rotation due to the circumferential length of the ramp (see FIGS. 3 and 4). Lateral shift will initiate approximately at B and terminate at C, about 90 further on. Further rotation of about 90 will bring that tooth of the driving collar 50 opposite the tooth thatslid down the ramp into contact with

tooth

80 or 81 of link actuator 56 at D. Rotation of the driving collar from D to B will move the link actuator to the new selected position for needle penetration at A.

Owing to: the location of the internal fin 91 on the link actuators 56 in the groove 90 on the driving collars 50, and, in addition, to the fins and 171 on the link possible unless the link actuators 56 are in the positions shown in FIGS. 3 and 4 where the driving

collar teeth

75 and 76 may progress down the

ramps

85 and 86. Thus the electromagnets 70 may be energized at D to prepare for a change in the lateral position of the driving collar 50, which will not begin to take place until point B is reached.

Having thus put forth the nature of the invention what is claimed herein is:

1. An adder mechanism comprising a housing, a drive shaft journaled in said housing, a plurality of adder links carried by said housing in side by side relationship spaced from said drive shaft, and adder links each having a thin section and a thick section, a plurality of link actuators in side by side relationship individually connected to said adder links encircling said drive shaft and spanning said space between said drive shaft and said adder links, adder spacers interposed between said adder links and carried in said housing in said selected position for connecting selected sections, means associated with said drive shaft and said link actuators for urging said link actuators and said adder links to a selected effective position for said thin and thick section of said adder links, and output means responsive to the total dimension of said adder spacers and said sections in said selected effective position.

2. An adder mechanism as claimed in claim 1 wherein said means for urging said link actuators includes:

a. a plurality of drive collars supported on said drive shaft to rotate therewith and selectively axially shiftable along said drive shaft between two locations, said drive collars being interposed between said link actuators, said drive collars having at least one tooth projecting therefrom internally of said link actuators;

b. said link actuators having a pair of oppositely disposed and axially spaced teeth on an internal surface thereof for selective engagement with said tooth of said drive collar depending upon said selected axial location of said drive collar whereby said link actuator is urged by the selective engagement of said teeth to a selected position; and,

c. means for selectively axially shifting said drive collar along said drive shaft between said two locations.

3. In a sewing machine having a frame, a needle bar gate supported in said frame for lateral oscillation, a needle bar supported in said gate for endwise reciprocation, drive means including means to drive said needle bar in endwise reciprocation, and means for driving said needle bar gate in lateral oscillation said means including:

An adder mechanism having a housing supported in said sewing machine frame, a drive shaft journaled in said housing driven by said sewing machine drive means, a plurality of adder links carried by said housing spaced from said drive shaft, said adder links each having a thin section and a thick section, a plurality of link actuators individually connected to said adder links encircling said drive shaft and spanning said space between said drive shaft and said adder links, adder spacers interposed between said adder links and carried in said housing in a selected effective position for connecting selected sections, means associated with said drive shaft and said link actuators for urging said link actuators and said adder links to a selected position for said thin and thick sections of said adder links, and output means responsive to the total dimension of 8 said adder spacers and said sections in said selected effective position for driving said needle bar gate in lateral oscillation.

4. in a sewing machine as claimed in claim 3, said sewing machine further including a feed system for feeding work material through said sewing machine wherein said adder mechanism includes a second plurality of adder links carried in said housing spaced from said drive shaft, said second plurality of adder links each having a thin section and a thick section, a second plurality of link actuators individually connected to said second plurality of adder links encircling said drive shaft and spanning said space between said drive shaft and said second plurality of adder links, means associated with said drive shaft and said link actuators for urging said second plurality of link actuators and adder links to a selected position for said thin and thick sections of said adder links, adder spacers interposed between said second plurality of adder links and carried in'said housing in said selected effective position for connecting selected sections, a fixed adder spacer means between said first plurality of adder links and said second plurality of adder link output means responsive to the total dimension of said adder spacers and said sections in said selected effective position for the second plurality of adder links for controlling said sewing machine feed system, and output means responsive to the total dimension of said adder spacers and said sections in said selected effective position for the first plurality of link adders for driving said needle bar gate in lateral oscillation.

Claims

2. An adder mechanism as claimed in claim 1 wherein said means for urging said link actuators includes: a. a plurality of drive collars supported on said drive shaft to rotate therewith and selectively axially shiftable along said drive shaft between two locations, said drive collars being interposed between said link actuators, said drive collars having at least one tooth projecting therefrom internally of said link actuators; b. said link actuators having a pair of oppositely disposed and axially spaced teeth on an internal surface thereof for selective engagement with said tooth of said drive collar depending upon said selected axial location of said drive collar whereby said link actuator is urged by the selective engagement of said teeth to a selected position; and, c. means for selectively axially shifting said drive collar along said drive shaft between said two locations.

3. In a sewing machine having a frame, a needle bar gate supported in said frame for lateral oscillation, a needle bar supported in said gate for endwise reciprocation, drive means including means to drive said needle bar in endwise reciprocation, and means for driving said needle bar gate in lateral oscillation said means including: An adder mechanism having a housing supported in said sewing machine frame, a drive shaft journaled in said housing driven by said sewing machine drive means, a plurality of adder links carried by said housing spaced from said drive shaft, said adder links each having a thin sectioN and a thick section, a plurality of link actuators individually connected to said adder links encircling said drive shaft and spanning said space between said drive shaft and said adder links, adder spacers interposed between said adder links and carried in said housing in a selected effective position for connecting selected sections, means associated with said drive shaft and said link actuators for urging said link actuators and said adder links to a selected position for said thin and thick sections of said adder links, and output means responsive to the total dimension of said adder spacers and said sections in said selected effective position for driving said needle bar gate in lateral oscillation.

4. In a sewing machine as claimed in claim 3, said sewing machine further including a feed system for feeding work material through said sewing machine wherein said adder mechanism includes a second plurality of adder links carried in said housing spaced from said drive shaft, said second plurality of adder links each having a thin section and a thick section, a second plurality of link actuators individually connected to said second plurality of adder links encircling said drive shaft and spanning said space between said drive shaft and said second plurality of adder links, means associated with said drive shaft and said link actuators for urging said second plurality of link actuators and adder links to a selected position for said thin and thick sections of said adder links, adder spacers interposed between said second plurality of adder links and carried in said housing in said selected effective position for connecting selected sections, a fixed adder spacer means between said first plurality of adder links and said second plurality of adder link output means responsive to the total dimension of said adder spacers and said sections in said selected effective position for the second plurality of adder links for controlling said sewing machine feed system, and output means responsive to the total dimension of said adder spacers and said sections in said selected effective position for the first plurality of link adders for driving said needle bar gate in lateral oscillation.