B
SECTION B — PERFORMING OPERATIONS; TRANSPORTING
 B01 - 
B07
Subsection index
LIQUID/LIQUID, LIQUID/GAS OR GAS/GAS SEPARATION
Method
General operationsB01D
by centrifugal force, using centrifuges or free-vortex apparatusB01D
using magnetic or electrostatic effectB03C
Apparatus
General operationsB01D
by centrifugal force, using centrifuges or free-vortex apparatusB04B, B04C
using magnetic or electrostatic effectB03C
SOLID/LIQUID OR SOLID/GAS SEPARATION
Method
General operationsB01D
by centrifugal forceB01D
using centrifuges or free-vortex apparatusB01D
using magnetic or electrostatic effectB03C
Apparatus
General operationsB01D
by centrifugal forceB01D
using centrifuges or free-vortex apparatusB04B, B04C
using magnetic or electrostatic effectB03C
SOLID/SOLID SEPARATION
Method
Dry methods
material in bulkB07B
Individual sortingB07C
Screening, sifting, pneumatic sortingB07B
using pneumatic tables or jigsB03B
by magnetic or electrostatic effectB03C
by centrifugal forceB07B
using centrifuges or free-vortex apparatusB07B
Wet methods
General operationsB03B
flotation, differential sedimentationB03D
screeningB07B
Combinations Dry methods - wet methodsB03B
Apparatus
Dry methods
material in bulkB07B
Individual sortingB07C
Screening, sifting, pneumatic sortingB07B
using pneumatic tables or jigsB03B
by magnetic or electrostatic effectB03C
by centrifugal forceB07B
using centrifuges or free-vortex apparatusB04B, B04C
Wet methods
General operationsB03B
flotation, differential sedimentationB03D
screeningB07B
Combinations Dry methods - wet methodsB03B
  
SHAPING
 B23
MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR (punching, perforating, making articles by processing sheet metal, tubes, or profiles B21D; wire-working B21F; making pins, needles, or nails B21G; making chains B21L; grinding B24)
 B23

Note(s)

  1. This class covers:
    • operations not provided for in any other class;
    • combinations of operations covered by different subclasses of classes B21-B24, which combinations are covered by subclass B23P, with the exception of subsidiary operations performed in conjunction with main operations covered by a single subclass;
    • features, specific to machine tools, which relate to a requirement or problem of a nature which is not peculiar to a particular kind of machine tool, e.g. feeding work, which are covered by subclass B23Q, although the realisation of these features may differ according to the kind of machine tool concerned. The said subclass covers such features, in general, even if the feature or a specific function, in any particular case, is to some extent peculiar to, or is claimed only for, machine tools designed for one particular operation; only in exceptional cases are such features classified in the subclass for the machine tool concerned. Certain features of this general nature are, however, referred to subclasses relating to particular metal-working operations, especially B23B, in which case the subclasses in question are not restricted, in respect of those features, to the kind of machine tool with which they are primarily concerned.
  2. In this class, the following terms or expressions are used with the meanings indicated:
    • "metal-working" covers the working of other materials unless the context requires otherwise;
    • "kind of operations" and similar expressions relate to such metal-working operations as boring, drilling, milling and grinding;
    • "kind of machine" means a machine designed for a particular kind of metal-working operation (e.g. a lathe);
    • "form of machine" means a machine of a particular kind adapted or arranged for a particular way of working or for particular work, e.g. face-plate lathe, tailstock lathe, turret lathe;
    • "different machines" covers different forms of machines for performing the same type of metal-working operation, e.g. vertical and horizontal boring machines.
  3. If details, components, or accessories have no essential feature specific to machine tools, the more general class, e.g. F16, takes precedence.
 B23Q
DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING (tools of the kind used in lathes or boring machines B23B 27/00); MACHINE TOOLS IN GENERAL, CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
 B23Q

Note(s)

  1. In this subclass, groups designating parts of machine tools cover machine tools characterised by constructional features of such parts.
  2. In this subclass, the following terms or expressions are used with the meanings indicated:
    • "controlling" means influencing a variable in any way, e.g. changing its direction or its value (including changing it to or from zero), maintaining it constant, limiting its range of variation;  [3]
    • "regulation" means maintaining a variable automatically at a desired value or within a desired range of values. The desired value or range may be fixed, or manually varied, or may vary with time according to a predetermined "programme" or according to variation of another variable. Regulation is a form of control;  [3]
    • "automatic control" is often used in the art as a synonym for regulation.  [3]
  3. Attention is drawn to the Notes following the title of class B23.
 B23Q
Subclass index
BASIC COMPONENTS OF MACHINE TOOLS 1/00, 9/00
DEVICES FOR SUPPORTING, HANDLING, OR FEEDING WORK OR TOOLS 3/00, 5/00, 7/00
AUXILIARY EQUIPMENT, SAFETY DEVICES 11/00, 13/00, 27/00
MEASURING; INDICATING; CONTROLLING
Controlling the movements of the tool or work 15/00, 16/00, 23/00
Indicating 17/00
COPYING 33/00, 35/00
MACHINES COMPRISING UNITS OR SUB-ASSEMBLIES, TRANSFER MACHINES, ASSOCIATIONS OF MACHINES OR UNITS 37/00, 39/00, 41/00
P:130 B23Q 1/00
Members which are comprised in the general build-up of a form of machine, particularly relatively large fixed members (B23Q 37/00 takes precedence)
 B23Q 1/01
·  Frames, beds, pillars or like members; Arrangement of ways  [6]
 B23Q 1/03
·  Stationary work or tool supports (B23Q 1/70 takes precedence; auxiliary tables B23Q 1/74; tailstocks B23B 23/00)  [6]
 B23Q 1/25
·  Movable or adjustable work or tool supports  [6]
 B23Q 1/26
·  ·  characterised by constructional features relating to the co-operation of relatively movable members; Means for preventing relative movement of such members  [6]
 B23Q 1/28
·  ·  ·  Means for securing sliding members in any desired position  [6]
 B23Q 1/30
·  ·  ·  controlled in conjunction with the feed mechanism  [6]
 B23Q 1/32
·  ·  ·  Relative movement obtained by co-operating spherical surfaces, e.g. ball-and-socket joints  [6]
 B23Q 1/34
·  ·  ·  Relative movement obtained by use of deformable elements, e.g. piezo-electric, magnetostrictive, elastic or thermally-dilatable elements (sensitive elements capable of producing movement or displacement for purposes not limited to measurement G12B 1/00)  [6]
 B23Q 1/36
·  ·  ·  ·  Springs  [6]
 B23Q 1/38
·  ·  ·  using fluid bearings or fluid cushion supports  [6]
 B23Q 1/40
·  ·  ·  using ball, roller or wheel arrangements  [6]
 B23Q 1/42
·  ·  ·  using T-, V-, dovetail-section or like guides (B23Q 1/40 takes precedence)  [6]
 B23Q 1/44
·  ·  using particular mechanisms (B23Q 1/26 takes precedence)  [6]
 B23Q 1/44

Note(s)

  1. In this group, the following expressions are used with the meaning indicated: [6]
    • "sliding pair" means a pair consisting of two elements operating in such a way that only straight line movement between both elements is possible; [6]
    • "rotating pair" means a pair consisting of two elements operating in such a way that only rotary movement between both elements is possible; [6]
    • "screw pair" means a pair consisting of two elements operating in such a way as to produce simultaneous rotation and axial translation between both elements. [6]
  2. In this group, where more than one pair of elements is provided on the same axis for the same kind of movement, the pairs are regarded as a single pair for the purposes of classification. [6]
 B23Q 1/46
·  ·  ·  with screw pairs  [6]
 B23Q 1/48
·  ·  ·  with sliding pairs and rotating pairs (B23Q 1/46 takes precedence)  [6]
 B23Q 1/50
·  ·  ·  with rotating pairs only  [6]
 B23Q 1/52
·  ·  ·  ·  a single rotating pair  [6]
 B23Q 1/54
·  ·  ·  ·  two rotating pairs only  [6]
 B23Q 1/56
·  ·  ·  with sliding pairs only  [6]
 B23Q 1/58
·  ·  ·  ·  a single sliding pair  [6]
 B23Q 1/60
·  ·  ·  ·  two sliding pairs only  [6]
 B23Q 1/62
·  ·  ·  ·  ·  with perpendicular axes, e.g. cross-slides  [6]
 B23Q 1/64
·  ·  characterised by the purpose of the movement (indexing equipment B23Q 16/02)  [6]
 B23Q 1/66
·  ·  ·  Work-tables interchangeably movable into operating positions  [6]
 B23Q 1/68
·  ·  ·  for withdrawing tool or work during reverse movement  [6]
 B23Q 1/70
·  Stationary or movable members for carrying working-spindles for attachment of tools or work (headstocks or the like, working-spindle supports B23B 19/00; working-spindles B23B 19/02)  [6]
 B23Q 1/72
·  Auxiliary arrangements; Interconnections between auxiliary tables and movable machine elements  [6]
 B23Q 1/74
·  ·  Auxiliary tables  [6]
 B23Q 1/76
·  ·  Steadies; Rests  [6]
P:110 B23Q 3/00
Devices holding, supporting, or positioning, work or tools, of a kind normally removable from the machine (work-tables or other parts, e.g. faceplates, normally not incorporating means for securing work B23Q 1/00; automatic position control B23Q 15/00; rotary tool heads for turning-machines B23B 3/24, B23B 3/26; non-driven tool holders B23B 29/00; general features of turrets B23B 29/24; tools or bench devices for fastening, connecting, disengaging or holding B25B)
 B23Q 3/02
·  for mounting on a work-table, tool-slide, or analogous part (B23Q 3/15 takes precedence)
 B23Q 3/04
·  ·  adjustable in inclination
 B23Q 3/06
·  ·  Work-clamping means
 B23Q 3/08
·  ·  ·  other than mechanically-actuated
 B23Q 3/10
·  ·  Auxiliary devices, e.g. bolsters, extension members
 B23Q 3/12
·  for securing to a spindle in general (B23Q 3/152 takes precedence; chucks B23B 31/02)
 B23Q 3/14
·  ·  Mandrels in general (expansion mandrels B23B 31/40)
 B23Q 3/15
·  Devices for holding work using magnetic or electric force acting directly on the work
 B23Q 3/152
·  ·  Rotary devices
 B23Q 3/154
·  ·  Stationary devices
 B23Q 3/155
·  Arrangements for automatic insertion or removal of tools
 B23Q 3/157
·  ·  of rotary tools
 B23Q 3/16
·  controlled in conjunction with the operation of the tool
 B23Q 3/18
·  for positioning only
P:70 B23Q 5/00
Driving or feeding mechanisms; Control arrangements therefor (automatic control B23Q 15/00; copying B23Q 33/00, B23Q 35/00; specially adapted for boring or drilling machines B23B 39/10, B23B 47/02)
 B23Q 5/02
·  Driving main working members
 B23Q 5/027
·  ·  reciprocating members  [2]
 B23Q 5/033
·  ·  ·  driven essentially by fluid pressure  [2]
 B23Q 5/04
·  ·  rotary shafts, e.g. working-spindles
 B23Q 5/06
·  ·  ·  driven essentially by fluid pressure or pneumatic power
 B23Q 5/08
·  ·  ·  ·  electrically controlled
 B23Q 5/10
·  ·  ·  driven essentially by electrical means
 B23Q 5/12
·  ·  ·  Mechanical drives with means for varying the speed ratio
 B23Q 5/14
·  ·  ·  ·  step-by-step
 B23Q 5/16
·  ·  ·  ·  infinitely-variable
 B23Q 5/18
·  ·  ·  ·  Devices for preselecting speed of working-spindle
 B23Q 5/20
·  ·  ·  Adjusting or stopping working-spindles in a predetermined position
 B23Q 5/22
·  Feeding members carrying tools or work
 B23Q 5/26
·  ·  Fluid-pressure drives  [3]
 B23Q 5/28
·  ·  Electric drives  [3]
 B23Q 5/32
·  ·  Feeding working-spindles (feeding working-spindle supports B23Q 5/34)  [3]
 B23Q 5/34
·  ·  Feeding other members supporting tools or work, e.g. saddles, tool-slides, through mechanical transmission  [3]
 B23Q 5/36
·  ·  ·  in which a servomotor forms an essential element  [3]
 B23Q 5/38
·  ·  ·  feeding continuously  [3]
 B23Q 5/40
·  ·  ·  ·  by feed shaft, e.g. lead screw  [3]
 B23Q 5/42
·  ·  ·  ·  ·  Mechanism associated with headstock  [3]
 B23Q 5/44
·  ·  ·  ·  ·  Mechanism associated with the moving member  [3]
 B23Q 5/46
·  ·  ·  ·  with variable speed ratio  [3]
 B23Q 5/48
·  ·  ·  ·  ·  by use of toothed gears  [3]
 B23Q 5/50
·  ·  ·  feeding step by step  [3]
 B23Q 5/52
·  ·  Limiting feed movement
 B23Q 5/54
·  Arrangements or details not restricted to group B23Q 5/02 or group B23Q 5/22 respectively
 B23Q 5/56
·  ·  Preventing backlash
 B23Q 5/58
·  ·  Safety devices
P:80 B23Q 7/00
Arrangements for handling work specially combined with or arranged in, or specially adapted for use in connection with, machine tools, e.g. for conveying, loading, positioning, discharging, sorting (incorporated in working-spindles B23B 13/00, B23B 19/02; for automatic or semi-automatic turning machines B23B 15/00)  [2]
 B23Q 7/02
·  by means of drums or rotating tables or discs
 B23Q 7/03
·  by means of endless chain conveyers (B23Q 7/16 takes precedence)  [2]
 B23Q 7/04
·  by means of grippers
 B23Q 7/05
·  by means of roller-ways (B23Q 7/16 takes precedence)  [2]
 B23Q 7/06
·  by means of pushers
 B23Q 7/08
·  by means of slides or chutes
 B23Q 7/10
·  by means of magazines
 B23Q 7/12
·  Sorting arrangements
 B23Q 7/14
·  co-ordinated in production lines
 B23Q 7/16
·  Loading work on to conveyers; Arranging work on conveyers, e.g. varying spacing between individual workpieces  [2]
 B23Q 7/18
·  ·  Orienting work on conveyers  [2]
P:90 B23Q 9/00
Arrangements for supporting or guiding portable metal-working machines or apparatus (for tapping pipes B23B 41/08; specially designed for drilling B23B 45/14)
 B23Q 9/02
·  for securing machines or apparatus to workpieces, or other parts, of particular shape, e.g. to beams of particular cross-section
 B23Q 11/00 - 
B23Q 13/00
Accessories
P:150 B23Q 11/00
Accessories fitted to machine tools for keeping tools or parts of the machine in good working condition or for cooling work; Safety devices specially combined with or arranged in, or specially adapted for use in connection with, machine tools (in respect of boring or drilling machines B23B 47/24, B23B 47/32 take precedence; safety devices in general F16P)
 B23Q 11/02
·  Devices for removing scrap from the cutting teeth of circular cutters
 B23Q 11/04
·  Arrangements preventing overload of tools, e.g. restricting load
 B23Q 11/06
·  Safety devices for circular cutters
 B23Q 11/08
·  Protective coverings for parts of machine tools; Splash guards
 B23Q 11/10
·  Arrangements for cooling or lubricating tools or work (incorporated in tools, see the relevant subclass for the tool)  [1,8]
 B23Q 11/12
·  Arrangements for cooling or lubricating parts of the machine (B23Q 11/14 takes precedence)  [1,8]
 B23Q 11/14
·  Methods or arrangements for maintaining a constant temperature in parts of machine tools  [1,8]
P:160 B23Q 13/00
Equipment for use with tools or cutters when not in operation, e.g. protectors for storage
 B23Q 15/00 - 
B23Q 27/00
Measuring; Indicating; Controlling  [3]
P:30 B23Q 15/00
Automatic control or regulation of feed movement, cutting velocity or position of tool or work  [3]
 B23Q 15/007
·  while the tool acts upon the workpiece  [3]
 B23Q 15/013
·  ·  Control or regulation of feed movement (B23Q 15/12 takes precedence)  [3]
 B23Q 15/02
·  ·  ·  according to the instantaneous size and the required size of the workpiece acted upon (B23Q 15/06 takes precedence)  [3]
 B23Q 15/04
·  ·  ·  according to the final size of the previously machined workpiece (B23Q 15/06 takes precedence)  [3]
 B23Q 15/06
·  ·  ·  according to measuring results produced by two or more gauging methods using different measuring principles, e.g. by both optical and mechanical gauging  [3]
 B23Q 15/08
·  ·  Control or regulation of cutting velocity (B23Q 15/12 takes precedence)  [3]
 B23Q 15/10
·  ·  ·  to maintain constant cutting velocity between tool and workpiece  [3]
 B23Q 15/12
·  ·  Adaptive control, i.e. adjusting itself to have a performance which is optimum according to a preassigned criterion  [3]
 B23Q 15/14
·  ·  Control or regulation of the orientation of the tool with respect to the work  [3]
 B23Q 15/16
·  ·  Compensation for wear of the tool  [3]
 B23Q 15/18
·  ·  Compensation of tool-deflection due to temperature or force  [3]
 B23Q 15/20
·  before or after the tool acts upon the workpiece  [3]
 B23Q 15/22
·  ·  Control or regulation of position of tool or workpiece  [3]
 B23Q 15/24
·  ·  ·  of linear position  [3]
 B23Q 15/26
·  ·  ·  of angular position  [3]
 B23Q 15/28
·  ·  with compensation for tool wear  [3]
P:100 B23Q 16/00
Equipment for precise positioning of tool or work into particular locations not otherwise provided for (automatic control or regulation of position of tool or work B23Q 15/22; arrangements for indicating or measuring existing or desired position of tool or work B23Q 17/22)  [4]
 B23Q 16/02
·  Indexing equipment (specially adapted for gear-cutting machines B23F 23/08)  [4]
 B23Q 16/04
·  ·  having intermediate members, e.g. pawls, for locking the relatively movable parts in the indexed position  [4]
 B23Q 16/06
·  ·  ·  Rotary indexing  [4]
 B23Q 16/08
·  ·  having means for clamping the relatively movable parts together in the indexed position  [4]
 B23Q 16/10
·  ·  ·  Rotary indexing  [4]
 B23Q 16/12
·  ·  using optics  [4]
P:140 B23Q 17/00
Arrangements for indicating or measuring on machine tools (for automatic control or regulation of feed movement, cutting velocity or position of tool or work B23Q 15/00)  [3,4]
 B23Q 17/09
·  for indicating or measuring cutting pressure or cutting-tool condition, e.g. cutting ability, load on tool (arrangements preventing overload of tools B23Q 11/04; devices for indicating failure of drills during boring B23B 49/00)  [4]
 B23Q 17/10
·  for indicating or measuring cutting speed or number of revolutions
 B23Q 17/12
·  for indicating or measuring vibration
 B23Q 17/20
·  for indicating or measuring workpiece characteristics, e.g. contour, dimension, hardness  [4]
 B23Q 17/22
·  for indicating or measuring existing or desired position of tool or work  [4]
 B23Q 17/24
·  using optics  [4]
P:120 B23Q 23/00
Arrangements for compensating for irregularities or wear, e.g. of ways, of setting mechanisms (automatic control B23Q 15/00)  [3]
P:20 B23Q 27/00
Geometrical mechanisms for the production of work of particular shapes, not fully provided for in another subclass
 B23Q 33/00 - 
B23Q 35/00
Copying
 B23Q 33/00 - 
B23Q 35/00

Note(s)

In groups B23Q 33/00 or B23Q 35/00, the following term is used with the meaning indicated:

  • "copying" covers the derivation of a required shape from a pattern, of the same or a different shape or scale, by a mechanism or equivalent means controlled by a member following the pattern. The pattern may be a model or drawing, or an element such as a cam incorporated in the operating mechanism of a machine. This term does not cover the derivation of a required shape from simple geometrical shapes, e.g. generating a cycloid by a rolling circle, which in general is provided for in group B23Q 27/00.

P:0 B23Q 33/00
Methods for copying
P:10 B23Q 35/00
Control systems or devices for copying directly from a pattern or a master model; Devices for use in copying manually
 B23Q 35/02
·  Copying discrete points from the pattern, e.g. for determining the position of holes to be drilled
 B23Q 35/04
·  using a feeler or the like travelling along the outline of the pattern, model or drawing; Feelers, patterns, or models therefor
 B23Q 35/06
·  ·  specially adapted for controlling successive operations, e.g. separate cuts, on a workpiece
 B23Q 35/08
·  ·  Means for transforming movement of the feeler or the like into feed movement of tool or work
 B23Q 35/10
·  ·  ·  mechanically only
 B23Q 35/12
·  ·  ·  involving electrical means (programme recording for copying purposes in a separate apparatus G05, G11)
 B23Q 35/121
·  ·  ·  ·  using mechanical sensing
 B23Q 35/122
·  ·  ·  ·  ·  the feeler opening or closing electrical contacts
 B23Q 35/123
·  ·  ·  ·  ·  the feeler varying the impedance in a circuit
 B23Q 35/124
·  ·  ·  ·  ·  ·  varying resistance
 B23Q 35/125
·  ·  ·  ·  ·  ·  varying capacitance
 B23Q 35/126
·  ·  ·  ·  ·  ·  varying inductance
 B23Q 35/127
·  ·  ·  ·  using non-mechanical sensing
 B23Q 35/128
·  ·  ·  ·  ·  Sensing by using optical means
 B23Q 35/129
·  ·  ·  ·  ·  Sensing by means of electric discharges
 B23Q 35/13
·  ·  ·  ·  ·  Sensing by using magnetic means
 B23Q 35/14
·  ·  ·  ·  controlling one or more electromotors
 B23Q 35/16
·  ·  ·  ·  controlling fluid motors
 B23Q 35/18
·  ·  ·  involving fluid means (B23Q 35/16 takes precedence)
 B23Q 35/20
·  ·  ·  with special means for varying the ratio of reproduction
 B23Q 35/22
·  ·  ·  specially adapted for compensating for wear of the tool
 B23Q 35/24
·  ·  Feelers; Feeler units
 B23Q 35/26
·  ·  ·  designed for physical contact with a pattern or a model
 B23Q 35/28
·  ·  ·  ·  for control of a mechanical copying system
 B23Q 35/30
·  ·  ·  ·  for control of an electrical or electro-hydraulic copying system
 B23Q 35/32
·  ·  ·  ·  ·  in which the feeler makes and breaks an electrical contact or contacts, e.g. with brush-type tracers
 B23Q 35/34
·  ·  ·  ·  ·  in which the feeler varies an electrical characteristic in a circuit, e.g. capacity, frequency
 B23Q 35/36
·  ·  ·  ·  for control of a hydraulic or pneumatic copying system
 B23Q 35/38
·  ·  ·  designed for sensing the pattern, model, or drawing without physical contact (sensing by means of a fluid jet B23Q 35/36)
 B23Q 35/40
·  ·  ·  ·  involving optical or photoelectrical systems
 B23Q 35/42
·  ·  Patterns; Master models
 B23Q 35/44
·  ·  ·  provided with means for adjusting the contact face, e.g. comprising flexible bands held by set-screws
 B23Q 35/46
·  ·  ·  Supporting devices therefor
 B23Q 35/48
·  using a feeler or the like travelling to-and-fro between opposite parts of the outline of the pattern, model, or drawing
 B23Q 37/00 - 
B23Q 41/00
Metal-working machines comprising units or sub-assemblies; Associations of metal-working machines or units
P:40 B23Q 37/00
Metal-working machines, or constructional combinations thereof, built-up from units designed so that at least some of the units can form parts of different machines or combinations; Units therefor in so far as the feature of interchangeability is important (features relating to particular metal-working operations, see the relevant subclasses, e.g. B23P 23/00)
P:50 B23Q 39/00
Metal-working machines incorporating a plurality of sub-assemblies, each capable of performing a metal-working operation (B23Q 33/00, B23P 23/00 take precedence; if the operations are similar and the kind of operation is essential, see the relevant subclass for the operation)
 B23Q 39/02
·  the sub-assemblies being capable of being brought to act at a single operating station
 B23Q 39/04
·  the sub-assemblies being arranged to operate simultaneously at different stations, e.g. with an annular work-table moved in steps (associations of machines connected only by work-transferring means B23Q 41/00)
P:60 B23Q 41/00
Combinations or associations of metal-working machines not directed to a particular result according to classes B21, B23, or B24 (B23Q 37/00, B23Q 39/00 take precedence; features relating to operations performed, if the different metal-working operations are of the same kind, see the subclass for the kind of operation, e.g. punching B21D, welding B23K, grinding B24B; features relating to technically specified combinations of different metal-working operations B23P 23/00)
 B23Q 41/02
·  Features relating to transfer of work between machines (arrangements for handling work for machine tools co-ordinated in production lines B23Q 7/14)
 B23Q 41/04
·  Features relating to relative arrangements of machines
 B23Q 41/06
·  Features relating to organisation of working of machines
 B23Q 41/08
·  Features relating to maintenance of efficient operation