US2001347A

US2001347A - Condenser winding machine

Info

Publication number: US2001347A
Application number: US685323A
Authority: US
Inventors: John Q Hoimes
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1933-08-16
Filing date: 1933-08-16
Publication date: 1935-05-14
Anticipated expiration: 1952-05-14

Description

J. Q. HOLMES CONDENSER WINDING MACHINE Filed Aug. 1e, 1933 '7 sheets-sheet' 1 INvENToR ZHL/Mgg ATTORNEY J. Q. HOLMES 2,001,347

May 14, 1935.

CONDENSER WINDING MACHINE Filed Aug. 16, 1933; 7 Sheets-Sheet 2` POM f ATTORNEY/4f lMay 14,- 1935. J. Q HOLMES 2,001,347

CONDENSER WINDING MACHINE Filed Aug. 16, 1933 7 shes-shet 5 i 'EE' INVENTOR /A/Z /727/ Mf5 May 14, 1935. J, Q. Homes l `CONDENSER WINDING MACHINE y Filed Aug 16, 1933 :'T'Sheets-Sheet 4 raid@ ATTORNEY/f Non N ma new, 3N

Sww N 09N mmm. MMM

INVENTOR Z #zu/M55 1 l l l Il 1 l I K 1LA575701/ May 14, 1935. J. Q. HOLMES CONDENSER WINDING MACHINE Filed Aug. 16, 1955 '7 Sheets-Sheet 5 MYR l \\.N QNXN NSN um. QN

N3 4 SN ATTORNEY/ .May 14, 193.5- v.1. Q. HOLMES v 2,001,347

coNDENsER wINDING MACHINE Filed Aug. 16, 1933 7 sheets-sheet 6 ATTORNEY/ INVENTOR f g' /UH/V @Hm/v1.55

May 14, 1935. J- Q HOLMES l 2,001,347

CONDENSER WINDING MACHINE Filed Aug. 16, 1935 7 Sheets-Shea?l 7 ?atented May 14, 1935 CONDENSER WINDING .lohn Q. Holmes, Anderson, ind., assigner, by mesne assignments, to General Motors Corporation, llletroit,l Mich., a corporation oi.' Delaware application aum@ is, icas, sei-ns1 No. 685,323

i2 claims. (ci. 24e-55) This invention relates to apparatus for winding strips of sheet material such as the thin strips of metal ioil alternating with strips of insulating material such as paper used in the manufacture 5. ci electrical condensers.

It is an object of the present invention to provide a winding apparatus having a mandrel upon which condensers may be readily wound and from which wound condensers may be readily removed. thus rendering obsolete the earlier practice of providing acore for each condenser and winding a. condenser upon a core which either became a permanent part of the condenser or necessitated subsequent removal from the condenser. The present invention is therefore an improvement upon the condenser winding machine of F. C. Kroeger et al., Patent No. 1,641,389, issued September 6, i927, wherein the first mentioned practice was pursued.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a -preferred embodiment ci one form of the present invention is clearly shown.

In the drawings:

Figs. 1, 2, and 3 taken together constitute a side elevation oi e. condenser winding machine embodying the present invention.

Fig. 4 is a plan view of a portion ci the winding machine.

Fig. 5 is a front view looking Ain the direction of arrow 5 in d, certain parts being shown in section, the section being taken on the line 5 5 oi Fig. l.

Figs. 5a and 5b are fragmentary sectional views of a detail of the machine.

Fig. 6 is a sectional view taken on the line 8 5 of Fig. 2.

Fig. 7 is a sectional view taken on the line 'l--l of Fig. l.

Fig. 8 is a fragmentary sectional view taken fore provides an enclosure for and supports rolls of tin foil or other metal foil and rolls of thin paper which provide the dielectric or insulation between the stripsof foil included in the condenser. The box 20 is provided at its under surface with mounting pads 23 by means oi which the box may be mounted upon a suitable hori- Azontal support so that the parts 'of the machine which require control and manipulation by the operator will be conveniently accessible. This support is not shownin the drawings but is preferably any suitable table which will support the machine at a suitable distance from the iloor. The box 2d with its cover 2l provides a substantia-ily dust proof enclosure for the condenser 1 material. Box 20 is preferably of metal such as cast iron and may be heated in any desirable manner such as by electrical resistance elements in order to assist in expelling some oi' the moisture from the condenser paper. As this heating means is not a part oi the present invention it is not disclosed. The iront end of box 20 is provided with a mounting pad 24, having a inished surface against which is bolted by screws 25 a frame 2lil for supporting the guides or chutes for the condenser material, the mandrel about which this material is wound, and the devices for reciprocating and turning the mandrel and for applying pressure to the condenser material as it is wound about the mandrel.

The devices for supporting the condenser material in box Zdand for guiding this material to the outside of the box will ilrst be described. The box 2@ incloses and supports two rolls of metal ioil, tin or aluminum, indicated by the dot-and-dash circles 3@ and Sii, and six rolls of condenser paper indicated by the dot-and-dash Acrcles'sl, Si, 33, in the upper row and 35, 33 and 3l in the lower row. The strips of material which are withdrawn from these supply rolls are designated by the roll referice numbers with the affix a, For example, the strip of tin foil heing withdrawn from the roll 30 is shown at 30a, thestrip of paperwithdrawn from the paper roll 3l is shown at da. Each supply vroll is mounted on a spindle, carrying the drum of a friction tensioning device which tends tofeed the condenser material in the desired taut condition. As all of these spindles are substantially alike, but one of them will be described, namely, the 'spindle which holds the supply roll 31, shown in section in Fig 6. The spindle l0 is supported by ball bearings 4i and 42, mounted within a. sleeve 63 which is formed integrally with the box 20. Spindle 40 is axially slidable in the bearings M and 42 and its position with respect to box 2B is controlled by a nui.; M, bearing Aagainst the bearing 42 and received by the threaded portion 45 of spindle I0. A spring 46 which is interposed between a washer 41 anda collar 48, pinned to spindle: 40, maintains nut 44 in engagement with bearing v42. It is apparent mounted preferablyon a wooden core 49. The

roll 31 and the core 49 are held against a disc 50, carried by a spindle 40 with the core supported upon an annular flange 5| which lines up core 49 concentric with spindle 40. A wedge 52 which is keyed to spindle 40 but slidable longitudinally relative thereto, is maintained in clamping engagement with core 49 by a nut 53, which is received by the threaded end 54 of spindle 40. Each disc 50 is provided with an annular flange 55, the outer surface of which provides a brake drum which is frictionally engaged by a friction member 56, carried by a lever 51 which is pivotally mounted at one end upon a stud 58 (see Fig. 2), secured tothe side wall of box 20. Attached to lever 51 is one end of a spring 60, having its other end attached to a link 6| which in turn is .attached to a screw 62. Screw 62 is slidable up and down with respect to the top of box 20, but is prevented from turning by'means of a set screw 63, having threaded engagement with a boss provided by the top of box 20, and having its inner end projecting into a groove 65 provided by screw 62. A nut 66 cooperates with the threaded upper end of screw 62, so that by turning the nut 66, screw 62 will move up and down to vary the tension of spring 60 and consequently the amount of friction produced by the engagement of member 56 with the annular flange 55. The brakes for the upper row of material supply rolls are the same as those of the lower row of supply rolls, with the exception that the brake levers are reversed in position and the links Bla are of course much shorter than the llink 6|, since the upper row of supply rolls is so much nearer the top of box 20. During the winding operation it is necessary to relieve the tension on the brakes by throwing the brake members 56 out of engagement with the brake drums 55. This is accomplished in one operation by de- A pressing a foot pedal, indicated diagrammatically at 10 in Fig. 1, the pedal 10 being preferably located near the floor and attached by a link 1| to the free end of a lever arm 12 which is attached to a shaft.13, supported by bearings 14 which are attached to the side wall of box 20, as best shown in Figs. 2 and 3. Shaft 13 carries a plurality ofngers 15, each of which is adapted to engage a brake lever 51. Just below the upper row of supply roll spindles there is a similar shaft 16, carrying fingers 15, and each of the shafts 13V and 16 carries an arm 11, located adjacent the front end of box 20. These arms -11`are connected by a link 18. It is therefore apparent that downward movement of link 1| will cause all of the ngers 15 to move downwardly and to press all ofthe brake levers 51 downwardly so as to permit the brake drums 55 to run freely. Spring 12a (see Fig. 1) returns the link 1| into inoperative position.

The spindle 40, which supports the foil supply roll .is provided with means for turning it independently of the other supply roll spindles. This means includes a screw, having a knurled head 19 which is so attached to spindle 40 as to permit adjustment of nut 44. Spindle 40 may be rotated by manipulating the knurled screw head 19 without turning nut 44, in order to move strip 30a independently of the other material. Between the rows of material supply rolls there are a number of shelves 8|, 82, 83, 84, 85 and 86 which are mounted upon bolts 8|a, 82a, 93a, 84a, 85a and 86a, respectively. Each bolt, such as the bolt 86a, shown in section in Fig. 6, has a head 88 bearing against an outer surface of the shelf 86, and by reason of turning down nut 89 on thescrew threaded end 90, the surface 90a of the shelf 86 is clamped against a boss 9|. Care is taken to locate the shelf bolts parallel to the axes of the supply roll spindles and to. construct the shelves so that the guiding surface, such as the surface 86h of shelf 86 will be parallel tospindle 40. This arrangement insures that the strips of condenser material are kept parallel to one another and to the supply rolls so as to keep the material as near straightand flatv as possible. It will be noted that the shelves assist in preventing dust or 'lint from dropping down on the strips of material as they pass from the supply rolls to the guide chutes, which will now be described.

'I'he frame 26 supports a rod |0|, carrying a chute 00, a/rod |02 carrying a chute |03, a rod |05 carrying a chute |04, and a rod |06 carrying a ch'ute |01. The front end wall of box 20 is provided with openings |08, |09, ||0 and permitting the-chutes |00, |03, |04 and |01, respectively, to project slightly into said front wall and to be supported thereby. I As will be apparent from Figs. 1 to 3 inclusive, the chute 00 guides the foil strip 30a, the chute |03 guides the three superimposed paper strips 3Ia, 32a and 33a, the chute |04 guides the foil strip 34a and the chute |01 guides the three superimposed paper strips a, 36a and31a. The rods |0|, |02, |05 and |06 are horizontally slidable across the frame 26, and are provided with adjusting nuts I2, H3, I4 and ||5,

-respectively. Each of these nuts is threaded onto one end of the chute supporting ,rods and is maintained in engagement with the upper surface of a side of frame 26 by means of a spring I6 which bears against the frame 26 and a collar I1, pinned to each chute supporting rod (see Fig. 9.) Each chute is provided with a material guiding groove ||8 and with mounting ears ||9. Dowel pins |20 pass through these ears and through the chute supporting `rod in order to locate the chute in correct relation to its shaft, and screws |20a` secure the ears and chute to the supporting rod, all as shown in Fig. 9. It is obvious that by turning the adjusting nuts, the chute may be shifted to the right or tothe left as viewed in Fig. 4, in order to align the condenser paper strips and to secure the proper location of the foil strips with respect to the paper. Since the chutes |00 and 04 carry foil, and the chutes |03 and |01 carry paper, these chutes are so labeled in Figs. l and '1 for ready reference.

In order to wind a condenser, .an operator takes hold of the various foil and paper strips which emerge from the chutes |06, |63, |64 and |01, and winds a few layers of these strips upon the mandrel by rotating the hand wheel |35 in theproper direction. After a few layers of the material `are thus wound upon the mandrel, the operator actuates the described brake release pedal 10 and at the same time actuates the referred foot clutch whereupon the mandrel |6|` is power driven. After the condenser has been wound the operator disengages the foot clutch' to stop further rotation ofthe mandrel, then separates the last layer of the condenser-material from the material supply with a knife and finally glues a layer of wrapping paper to the condenser in order to prevent the condenserv layers from unwrapping. Such wrapping paper may be applied in the manner disclosed in the l'patent to F. C. Kroeger, No. 1,641,389, issued September 6, 1927. The condenser now has to be removed from the machine to make room for the winding of another condenser. To provide for reacw removal 'of a wound condenser from the machine, spindle |60 which carries the mandrel is moved longitudinally in the direction of arrow |60 sunlciently to clear mandrel 5| entirely from the condenser so that the same may be removed in a direction at right angles to its own axis.v As best shown in Figs. l, 4 and 5 a bracket |6| is attached by bolts 92 to a side wall of bracket 26. Attached to this bracket |6| by screws |62a is a cylinder |93 which receives a piston |94, having a piston rod |96, one end of which is guided vfor longitudinal movement ina sleeve bearing |61, extending from and integral with bracket |6|, as best shown in Fig. l. An aperture |66 in bracket 25 is provided for the reception of the piston rod when in the position shown in Fig. 5.

'Piston |64 is urged into the position shown in Fig. 5 'by a compression spring |66, interposed between said piston and the end wall 206 of cylinder |63. A cylinder cover- 26| is secured to the cylinder by screws 202 and seals the same, providing only for the passage ofthe piston rod into the cylinder. Attached tothe piston rod |66 by a bolt 203 is a member 204, the forky 205 of which embraces a block 206 and is secured thereto by screws 261. Block 206 is slidable longitudinally on sleeve |62. A screw pin 208, received by block '206, projects through a longitudinal slot 206 of sleeve |62 and into-an annular groove 2|0, pro- V2|2. aconduit 2|3, a second conventional Powell blow-gun 2|4 which is in every detail like valve 2 I2, and a conduit 2 5 which leads to an entrance duct 2 I6 communicating with the cylinder cham ber 2|?. Referring to Figs. 5a and 5b,.there is shown valve 2|2. A sliding valve 2| la which is provided with a push button 2|6 is normally urged into engagement with a valve seat 2|2a by means of a spring 2|3a, interposed between the valve body and said push button. This valve 2| la normally intercepts communication between a central passage 2 |4a which communicates with conduit 2 I8, and a passage'2l5a which communicates with conduits 2| However, passage-2|4a is normally in communication with the atmos phere by intermediation of an annular groove 2|8a oi. the valve 2| la and a communicating vent 2|6a in the valve body. Upon depression of the valve by an Voperator into the position shown in Fig. 5b against the tendency of spring 2|3a, fluid pressure is permitted to now through conduit 2| I, passage 2| 5a pastthe valve seat and through passage 2|4a to conduit 2|6, whereas the vent 2| 6a is intercepted from communication with passage 2|4a by the stem oi' the'depressed valve 2||a.

When the operator releases valve 2| |a in cie-v 2|4 are arranged in tandem fashion with the result that in order to provide communication 5 between the fluid pressure supply and cylinder chamber 2|1, both valves have to be actuated simultaneously. The valves have been so spaced from each other that it is impossible for the operator to actuate the push buttons 2|8 with one' hand. It is therefore apparent that in order,` -to admit fluid pressure to cylinder chamber 2 i1., the

operator has to use both hands for simultaneously actuating the valves. Upon release of'one.

of the Valves by the operator the cylinder is immediately vented through the released valve as can be readily understood from the foregoing description and the compression spring |99 moves the piston and therewith the mandrel into the position shown in Fig. ,5 much faster than the operator could reach the mandrel with the hand which released one of the push-buttons of the valves. It is therefore obvious that the tandem arrangement of the two valves serves for a safety purpose, namely, to prevent the operators hand from getting caught between the head |55 and the comparatively thin mandrel |5| whilethe latter moves into the position shown in Fig. 5.

Upon simultaneous actuation of both valves, the

mandrel |5| rapidly recedes in the direction rof arrow |90. During the early part of such receding movement of the mandrel, the end surface |13 of the wound condenser will strike against the end surface |12 of the cap |10, and upon continued receding movement of the mandrel the condenser will be stripped off said mandrel and finally drop vertically upon the surface 26a of bracket 26 from where it is removed. Subsequently the operator releases one or both of `the push buttons 2|6 of the valves which results in movement of the. mandrel from most retracted ,position into the position shown in Fig, 5, ready to receive the layers of the next condenser to be wound. Y

A gauge 220 is provided which indicates to the operator the increasing number of layers of material during the winding of the condenser so that the operator may stop .the rotation of the mandrel at the proper time and in the earlier described manner after a predetermined number of layers of material is wound upon said mandrel. This gauge may be of any well known' type and in the present instance comprises a pointer` 22| rotatable about an axis 222 and driven by a worm wheel 223 which is in .constant mesh with a worm 224 mounted in any suitable manner on spindle |40, as best shown in Fig. 5. Intermediate the worm wheel 223 and the pointer 22| is 'a stationary graduated plate 225, the graduation thereof starting with zero and representing the actual number of revolutions of the mandrel which is analogous to the number of layers of material wound thereon. After the winding of a condenser the pointer 22| is always set back into alignment with zero, ready for the winding of the next condenser.

After the initial layers of condenser are wound manually upon the mandrel |5| and before the operator connects said mandrel with the earlier mentioned power drive, he presses a metallic roller 230 against the initially wound layers of material on the mandrel so as to pack down or roll down the following layers of power wound condenser material. This metallic roller' 230 which is of substantial weight is loosely mounted on a rod 23| (see Fig. 10), having reduced k230. order to adjust the location of the rod 23| so threaded portions 232, which are received by notches provided in the arms 233'and234 of

levers

235 and 236, respectively. A nut 231, when tightened-causes the shoulderv 238 of rod 23| to engage arm 234, and a nut 239, when tightened, causes the arm 233 to be clamped against a spacer 240 which also bears against the roller Screws 24| and 242 may be turned in that its axisand therewith the axis of roller 230 will be parallel with the mandrel |5| to insure that the roller bears as equally as possible upon the condenser winding material on the mandrel. In order to apply pressure to the roller 230 during the winding operation and to throw the roller into inoperative position while a condenser is being removed from the machine, there is provided a lever 243 attached to a shaft 244 which is carried by the frame 26 as best shown in Fig. 7. Shaft 244 carries

hubs

245 and 246. having formed integrally therewith

tubes

24 and 248, respectively, which telescope with tubes 243`

Springs

255 and 256, located in the

tubes

241 and 243, respectively. Obviously by adjusting the screws 253 vand 254, the tendency of the

springs

255 and 256 to separate the respective telescoping tubes, which enclose them,'can be varied. 'Ihe hub 25| carries studs 251 upon which are mounted axially aligned rollers 256 engaging arcuate slots 259 which, as shown in Fig. 1 are provided in each of the arms 260, forming a part of lever 235. The hub 252 is also provided with studs 26| and rollers 262 which engage within arcuate slots similar to the slots 255, these slots being provided in the arms 263, forming a part of lever 236. The

levers

235 and 236 are pinned with their arcuate slots in alignment to a shaft 264 lwhich is journaled in frame 26 and parallel to` the mandrel |5|. When the lever 243 is in the position shown in Fig. 1, the roller 236 is in position to bear against the condenser material as. it is wound upon the core. This pressure will vary somewhat as the condenser increases in diameter but such variation will not adversely affect the process. The pressure exerted by roller 230 against the material on the mandrel is sunlcient to tend to keep all of the wrinkles ironed outV from the paper and foil as they are wound upon the mandrel, and to cause the condenser materials to be wound in compact fo'rm with air spaces or pockets reduced to a minimum'. When the lever 243 is rocked clockwise as viewed in Fig.l1, until it engages a stud 210, carried by frame 26, the

levers

235 and 236 willbe rotated counterclockwise as viewed in Fig; 1, thus causing the roller 230 to be moved into inoperative position to facilitate removal of the condenser. The spring 255 will yieldingly hold the lever 243 in engagement with stud 210 because the axis of said spring will then lie to the right (as viewed in Iiig. 1) of a line connecting the axes of

shafts

244 and 264, and the spring 255 will therefore tend to rotate the

levers

235 and 236 counter- 1. In 'a winding machine, the-combination of a stop; an axially movable sleeve yieldingly urged into engagement with the stop; a mandrel for winding layers of material thereon, said mandrel being journaled in said sleeve and movable axially relative thereto; spring means urging the mandrel in one direction; and means for moving the mandrel in the opposite direction whereby the wound object on the mandrel engages the sleeve and tends to move the same away from the stop thereby being stripped oil the mandrel.

2. In awinding machine, the combination of a stop; an axially-movable sleeve yieldingly urged into engagement with the stop and having a longitudinal slot; a mandrel for winding layers of material thereon, said mandrel being journaled in said sleeve and movable axially relative thereto and having an annular groove; spring means urging the mandrel in one direction; and

. reciprocable means including a screw pin projecting through the slot of the sleeve and into the annular groove of the mandrel for moving the latter`in the opposite direction whereby thewound object on the'mandrelengages the sleeve 'and tends to move the same away from the stop thereby being stripped off the mandrel.

3. In a winding machine, the combination of a stop; an axially movable sleeve yieldingly urged into engagement with the stop and having a longitudinal slot; 'a mandrel for winding layers of Y material thereon,A said mandrel being journaled in said sleeve and movable axiallyfrelative'thereto and having an annular groove; a block slidably mounted upon the sleeve; a screw pin received by the rblocl-r and projecting through the slot of the sleeve and into the annular groove of the mandrel; spring means urging the block in one direction; and means for movingthe block in the opposite direction whereby the wound object on the mandrel engages the sleeve and tends to move the same away from the stop thereby being stripped oiI the mandrel.

4. In a winding machine, the combination of a stop; an axially movable sleeve yieldingly urged into engagement with the stop and having a 1onceived by the block and projecting through the4 slot of the sleeve and into the an'nular groove of the mandrel; a cylinder having a piston therein connected to the block for reciprocation of the latter; a spring in said cylinder urging the piston in one direction; and means for admitting fluid pressure to the cylinderso as to move the piston in the opposite direction whereby the wound object on the moving mandrel engages the sleeve and tends to move the same away from the ,stop thereby being strippedv oli the mandrel.

5. In a winding machine, the combination of a reciprocable mandrel for winding materia thereon; means including a cylinderand a'. piston therein for reciprocating the mandrel; `a spring in said cylinder-urging the piston in one direction; and means for admitting uid pressure to said cylinder for moving thepiston in the opposite direction, said means including two manually operable valves connected in tandem fashion and spaced apart a distance greater than` the expanse o! a human hand; nd means preventing longitudinal movement of the wound 'object in .said opposite direction relative to the mandrel whereby the object is stripped oa the mandrel upon movement of the latter in said opposite direction.

6. In a winding machine, the combination of a rotatable and axially reciprocable mandrel for winding material thereon; abar :in Aaxial alignment with the mandrel and providing a driving center for the latter, said barbeing. .movable axially within pre-assigned limits; vyielding means urging the mandrel toward said bam-and yielding means urging the lbar toward the mandrel.-

7. In a winding machine, the combination of an axially. reciprocable and rotatable mandrel for winding material thereon, one end of said mandrel being provided with opposite tapered.

secured over the grooved end of the driving center, said ring engaging the stop when said driving center is moved by the approachingmandrel a certain distance against the tendency of the yielding means to urge said driving center toward the mandrel.`

8. In. a'winding machine, the combination of a reciprocable mandrel for winding layers of material thereon; yielding stop means for pre'- venting longitudinal movement of the wound object in one direction relative to themandrel;

and yielding means 4for moving the mandrel in jeither direction, the wound object being stripped oi the mandrel-upon engagement with said stop means during movement Aof the mandrel in said one direction.

9. In a winding machine, the combination of a reciprocable mandrel for winding -layers of material thereon; yielding stop means for preventing longitudinal movement of the wound object in one direction relative to the mandrel; spring means urging the mandrel in the opposite direction; and iiuid pressure operated means for moving the mandrel in said one direction whereby the wound object-is stripped-o5 the mandrel upon engagement with saidl stop means.

10. In a winding machine, the combination of a stop; an axially movable sleeve yieldingly urged into engagement with the stop and having a longitudinal slot; a. mandrel forwinding layers of material thereon, said mandrel being journaled in said sleeve and movable axially relative thereto and having an annular groove; and yielding reciprocating means including a screw pin pro- -jecting through the slot in the sleeve and into the annular groove of the mandrel for reciprocating the latter, the wound object on the mandrel engaging the sleeve and tending to move the same away from the stop' during movement of the mandrel in a certain direction whereby said wound object is stripped off the mandrel.

object in said one direction relative to the mandrel whereby the object is stripped on the mandrel upon movement of the latter in said one direction; and two manually operable controls for rendering the power operated means effective, said controls being spaced apart a distance greater than the expanse of a human hand and being so associated with the power operated means that both controls have to be operated to render said power operated means eiective.

12. In a winding machine, the combination of a reciprocable mandrel for winding material thereon; power operated means for moving the mandrel in one direction; yielding means urging the mandrel in the opposite direction; means for preventing longitudinal movement of the wound object in said one direction relative to the mandrel .whereby the object is stripped o!! the man- `drel upon movement of the latter in saizkne direction; and. two manually operable controls for rendering the power operated means effective, said controls normally rendering the power operated means ineffective and being spaced aparty a distance greater than the expanse of a human hand and being so associated with the power operated means that both controls have to be operated to render said power operated means effective.

JOHN Q. HOLMES.