16 



HARDWOOD RECORD 



September 10. 1922 



in the center, a building of the multi-storied type should not be 

 over 50 to 60 feet wide. 



It lias been shown many times that excessive vibration not only 

 causes rapid depreciation of machinery but also interferes mate- 

 rially with the quantity and quality of the product. Therefore, a 

 building should be designed not only with considerations of 

 strength in mind, but also rigidity and absence of deflection. If 

 shafting and pulleys are used to transmit power, the floor struc- 

 tures should be laid out with this end in view, providing ample head 

 room and substantial supporting members for shaft hangers and 

 bearings. 



Of the types of construction in use, the reinforced concrete build- 

 ing probably best complies with the above requirements of a good 

 building, although a properly designed slow burning mill type makes 

 a very satisfactory building and has one advantage over the rein- 

 forced concrete, in that machinery, shafting and equipment are 

 more easily installed and alterations to machinery arrangement 

 made. 



Important Points of Machinery Layou'; 

 Much has been written concerning the layout of machinery in 

 a woodworking plant to obtain efficient production and prevent 

 accidents, consequently it will probably only be desirable at this 

 time to emphasize some of the more important points to be kept 

 in mind. In the first place machining should be carefully chosen 

 for the work which it is desired to perform. Some machines are 

 suitable for performing various operations, but wherever possible 

 machines should be chosen for specific operations as it is often 

 difficult to locate a machine performing several operations so as to 

 obtain an efficient and orderly flow of material through the plant. 

 It is also bad practice from a safety standpoint, as it is difficult 

 if not impossible to design guards suitable for all the operations of 

 which a machine is capable and if various guards are supplied 

 suiting these various operations they must necessarily be of a tem- 

 porary nature and are likely to be removed and not used. 



It has also been my observation that machines which are pro- 

 vided with efficient guards by the manufacturers are more desir- 

 able than machines which have to have guards built by the pur- 

 chaser. Home-made guards are frequently unsubstantial and do 

 not entirely serve the purpose for which they are intended. Chain 

 drive and gear guards in particular should be installed by the 

 manufacturer, for they should preferably enclose the gear or chain 

 drive completely. Such a guard not only serves to protect the 

 workman but also materially affects the life of the machine by keep- 

 ing dust and dirt from the bearings and other moving parts. 



In laying out the machinery in a new machine room or re- 

 arranging it in an old room, with the end in view of obtaining the 

 most efficient layout, a routing chart should be drawn up. This 

 routing chart should list each separate part entering into the fin- 

 ished product with the proposed volume of manufacture per unit of 

 time. Such a routing chart giving the sequence of operations will 

 establish in a general way the sequence or arrangement of the 

 various tools and machines throughout the department. 

 Paper Templet Is Helpful 

 A paper templet, to scale should be made of each article of equip- 

 ment, such as all machines, tools, benches, racks, etc. Each templet 

 should indicate the name of the machine or operation, the path of 

 the product thru the machine, the point of application of power, 

 position of operator, and position of helper, if any. A floor plan 

 of the machine room to the same scale as the templets should be 

 prepared and then the templets placed on this plan and moved about 

 and located in accordance with the routing chart until the most 

 satisfactory arrangement is found, the marks on the templets allow- 

 ing the machines to be set in proper relation to flow of product, 

 power supply, lighting, etc. 



After an arrangement of the equipment has been completed a 

 careful study should be made of how the product is to be trans- 

 ported from machine to machine, making ample provision for aisle- 

 ways and location of trucks at machines to allow of efficient 

 handling of material in and out of machines. Consideration should 

 also be given to the necessity of providing spaces for accumulation 



of material between machines where the speed of handling varies. 

 The next important problem in laying out a machine room is to 

 decide on the method of transmitting power to the various machines. 

 There are in general two methods of driving machinery — shafting, 

 pulleys, and belting and the electric drive. The electric drive may 

 be further divided into two classes — the group drive and the indi- 

 vidual drive. The decision as to which tj-pe of drive to use is 

 dependent on several factors. In large plants with widely dis- 

 tributed machine rooms the electric individual or group drive is 

 practically the only means of transmitting power efficiently and 

 economically. In small and moderate sized plants the most ef- 

 ficient method of transmitting power is undoubtedly by means of 

 line shafting, pulley and belts. 



The transmission of power is one of the few features of a plant 

 where safety and efficiency may seem to some antagonistic. 

 Electric Transmission Is Preferable 

 Electric transmission, properly designed and installed, is un- 

 doubtedly preferable from a safety standpoint to a multitude of 

 pulleys and belts and possibly if proper statistics were available 

 it could be shown that electric drive was the most efficient from 

 the standpoint of cost when taking into consideration the fewer 

 accidents resulting from the electric drive than from lino shaft 

 drive. 



In any event the decision as to the proper method of transmitting 

 power in any plant must be made upon a proper consideration of 

 the various factors involved, the utmost safety and efficiency being 

 kept in mind at all times. 



If line shaft drive be the final decision, it goes without saying 

 that every means should be adapted for preventing accidents such 

 as providing proper guards for belts and pulleys; using safety type 

 set screws; cutting off projecting keys; covering up unused sec- 

 tions of keyways; and covering up or otherwise guarding all revolv- 

 ing parts which otherwise are likely to catch a man's clothing. 



Another feature which will add materially to the safety of a 

 line shaft installation is an automatic stop valve on the engine 

 with electric tripping device. By locating push button stations 

 frequently throughout the plant, the engine and consequently all 

 machinery may be stopped at a moment's notice and many acci- 

 dents which would otherwise prove serious to both men and machin- 

 ery be "nipped in the bud." 



While, as pointed out above, the electrical transmission of power, 

 when properly designed and installed, is better from the safety 

 standpoint than line shaft drive, yet if poorly installed it may be 

 more of a menace than pulleys and belting. In the first place all 

 electric wiring in a woodworking plant should be installed in rigid 

 metallic conduit. Open wiring is always dangerous to both men 

 and plant and particularly so when inflamable dust may so easily be 

 ignited by sparks. All motors of the direct current or slip ring 

 alternating current type should be of the enclosed pattern in order 

 to avoid danger from fire caused by sparks from the brushes. The 

 squirrel cage induction motor may well be enclosed also to keep out 

 accumulations of dust and dirt from the windings although the 

 danger from sparks is not so prevalent as with the types above 

 mentioned. 



Avoid Open Switches 

 The motor starting equipment should also receive thoughtful 

 study and all types of open switches and starters with exposed live 

 parts avoided as one would the plague. Such equipment is a con- 

 stant menace to both plant and men and should not be tolerated 

 in this day and age. 



Motors, unless connected direct to the machines which they drive, 

 should be located overhead on suitable brackets or platforms and 

 the platforms should be large enough in all cases so as to provide 

 ample room for the repair man. Motor compensators or starters 

 should be of the remote push button control type and should be 

 located on the platform with the motor. This places them in a 

 position where they cannot easily be tampered with and the only 

 part of the equipment with which the workmen is concerned is the 

 push button control station near his machine. Where group driv- 

 ing of machines is used it is advisable to use two or more push 



