US3376072A

US3376072A - Boring type mining machine having mechanically driven horizontal rotary trimmer bars

Info

Publication number: US3376072A
Application number: US512893A
Authority: US
Inventors: Jr Jerry Karlovsky
Original assignee: National Mine Service Co
Current assignee: National Mine Service Co
Priority date: 1965-12-10
Filing date: 1965-12-10
Publication date: 1968-04-02
Anticipated expiration: 1985-04-02
Also published as: FR1508154A

Description

April 2, 1968 J. KARLOVSKY. JR 3,376,072

BORING TYPE MINING MACHINE HAVING MECHANICALLY DRIVEN HORIZONTAL ROTARY TRIMMER BARS Filed Dec. 10, 1965 6 Sheets-Shem 1 O o O Q! o o N) O Q $1 0 0 a 00 o o 0 Q v a n3 5 Q a a a O O0 a Q 0 S3 0 0Q u '7\ Q DD 7 O c an H D I Q W C I 5 m POD 1 a J 1: 5 F

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JERRY/QRLOVSKnJP. BY

ApriE 2, 1%68 3,376,072 RLVEN .J. KARLOVSKY. JR BORING TYPE MINING MACHINE HAVING MBCHANICALLY D HORIZONTAL ROTARY TRIMMER BARS 6 Sheets-Sheet 2 Filed Dec. 10, 1965 g? INVENTOR. J5me Y finch/ K; Jet

J. KARLOVSKY. JR G MACHINE HAVING MECHANICALLY 3,3 76,072 DRlVEN April 2, 1968 BORING TYPE MININ Filed Dec. 10, 1965 INVENTOR. J's/am Mean/51w: J2:

April 2, 1968 J. KARLOVSKY, JR 3,376,072

BORING TYPE MINING MACHINE HAVING MECHANICALLY. DRIVEN HORIZONTAL ROTARY TRIMMER BARS 6 Sheets-Shem 4 Filed Dec. 10, 1965 INVENTOR. JERRY /6 movsx J? Apnl 2, 1968 .1. KARLOVSKY. JR 3,376,072

BORING TYPE MINING MACHINE HAVING MECHANICALLY DRIVEN HORIZONTAL ROTARY TRIMMER BARS Filed Dec. 10, 1965 6 Sheets-Shem a INVENTOR. Jse/QY/(QeLOI/SKnJEI a ls April 2, 1968 Filed Dec. 10, 1965 J. KARLOVSKY. JR BORING TYPE MINING MACHINE HAVING MECHANICALLY DRIVEN HORIZONTAL ROTARY TRIMMER BARS 6 Sheets-Sheet b' INVENTOR. Jseer muons (5 grr-aeA sf' United States Patent ABSCT OF THE DISCLOSURE A 'boring type mining machine having mechanically driven horizontal trimmer bars with a disconnect means. The trimmer bars are drivingly connected to the gearing in the main transmission by gearing in an auxiliary transmission secured to the side walls of the main transmission and shafting extending forwardly from the auxiliary trans mission. The s'hafting is drivingly connected to the trimmer bars and is located along the side of the mining machine. A shear pin type disconnect means forms a part of the sha-fting and is operable to disconnect the trimmer bars from the transmission. The disconnect means is lo cated along the side of the mining machine and is accessible from the side of the machine and rearwardly of the boring heads.

This invention relates to a boring type mining machine having mechanically driven horizontal trimmer bars and more particularly to a boring type mining machine having mechanically driven horizontal trimmer bars with externally positioned disconnect means to disconnect the rotary trimmer bars from the drive means.

Boring type mining machines having a plurality of boring heads extending forwardly therefrom form a plurality of contiguous and overlapping bores in the mine face. There remains between the plurality of bores depending and upstanding cusps of unmined material. Horizontally extending trimmer chains positioned adjacent the upper and lower limits of the bores have been used in the past to dislodge the depending and upstanding cusps of unmined material. The power requirements for operating the boring type mining machines with trimmer chains are substantial. For example, requirements of between 300 and 400 amps. per drive motor on the mining machine is normal with frequent surges of power in excess of 500 amps. being required. Where horizontal trimmer bars, also referred to as drum cutters, are used in lieu of the trimmer chains, the power requirements are reduced substantially. For example, a boring type mining machine equipped with drum cutters requires approximately 250 amps. per drive motor and at times substantially less than this amount of power is required.

In addition to the substantial reduction in power requirements, the size consist of the dislodged material is considerably larger than that produced with boring type mining machines equipped with trimmer chains. It is believed that the larger size consist is obtained because the lower drum cutter quickly feeds the dislodged material into the conveyor before the dislodged material is further reduced in size by the action ofthe boring heads.

Substantial maintenance problems are encountered, however when the drum cutters are mechanically connected to and driven by the drive motors for the boring heads. For example, the drum cutters frequently encounter strata of material more difiicult to mine or dislodge when compared with the material being dislodged by the rotary boring heads. This may subject the driving connections to forces that exceed thestructural limits of the gearing connecting the drum cutters to the drive motors and cause failure in the gearing. To repair the damaged gear- 3,376,072 Patented Apr. 2, 1968 ing the mining machine must be moved rearwardly away from the mine face to a location where the driving connections located on the front portion of the mining machine may be dismantled. Repairs of this type are both expensive and time consuming. With the hereinafter described invention there is provided a boring type mining machine with mechancally driven drum cutters that have a disconnect means for disengaging the drum cutters from the drive motors when the driving connections are subjected to a predetermined force. The drum cutters may be easily and quickly reconnected to the drive motors without moving the mining machine rearwardly away from the mine face.

Briefly, this invention comprises a boring type mining machine having a plurality of boring heads extending forwardly therefrom. The horizontal extending drum cutters are connected to the drive motors through the gearing in the main trans-mission and through gearing in an auxiliary transmission. Power is transmitted from the gearing in the main transmission to the auxiliary transmission and from the auxiliary transmission to the upper and lower drum cutters. There are externally positioned disconnect means associated with the driving connections in the auxiliary transmission that disconnects the input shaft of the auxiliary transmission from one or both of the auxiliary transmission output shafts when the driving connections are subjected to forces in excess of predeter mined forces. The disengaged driving connections within the auxiliary transmission may be quickly reconnected without moving the mining machine rearwardly away from the mine face.

Accordingly, the principal object of this invention is to provide a boring type mining machine having a plurality of boring heads extending forwardly therefrom and horizontally extending rotary trimmer bars that are mechanically driven by the drive motors for the boring heads and a disconnecting means for disengaging the drum cutters from the drive motors.

Another object of this invention is to provide a drive mechanism for the horizontally extending drum cutters that includes a disconnecting means operable to disconnect the drum cutters from the drive means when the driving connections are subjected to forces above a predetermined force.

A further object of this invention is to provide mechanically driven drum cutters for a boring type mining machine that are adjustable vertically and include a shear pin drive connection for protecting the mechanical drive from forces exceeding the structural limits of the gearing in the mechanical connections between the drum cutters and the drive motors.

These and other objects and advantages of this invention will be more completely disclosed and described in the following specification, the accompanying drawings and the appended claims.

In the drawings:

FIGURE 1 is a view in front elevation of my boring type mining machine having horizontally extending drum cutters.

FIGURE 2 is a fragmentary side view of the boring type mining machine shown in FIGURE 1 illustrating the mechanical drive connections between the main trans mission and the drum cutters.

FIGURE 3 is a fragmentary perspective view illustrating in detail the vertical auxiliary transmission'and the shear pin-disconnect means for the mechanical drive between the main transmission and the drum cutters.

FIGURE 4 is a fragmentary plan view of the gearing within the main transmission illustrating the gearing arrangement within the main transmission and the input shaft for the gearing within the auxiliary transmission.

FIGURE 5 is a fragmentary view in side elevation partially in section illustrating the driving connections between the main transmission and the drum cutters.

FIGURE 6 is a fragmentary view in front elevation illustrating the manner in which the drum cutter is driven by the output shaft from the auxiliary transmission.

Referring to the drawings and particularly FIGURES 1, 2 and 3 there is illustrated a boring type mining machine generally designated by the numeral 10 that has a mobile body portion 12 that is mounted on endless tracks 14. Secured to the front portion of the frame 12 is a main transmission housing 16 for the gearing and shafting associated with the boring heads generally designated by the

numerals

18, 20 and 22. Drive motors 24 are suitably supported on the main frame 12 and are connected to the gearing within the main transmission housing 16. The boring heads 18, 20 and 22 are suitably journaled in the transmission housing 16 and extend forwardly therefrom. The boring heads 18 and 20 have a plurality of radially extending arms 26 on which are telescopically positioned cutter elements 28. Suitable means are provided to adjust the cutter elements 28 radially relative on the arms 26. Arranged coaxially on the

boring heads

18 and 20 are core bursters 38 with cutter elements 32 extending forwardly therefrom. The core bursters have axial passageways 34 therethrough for receiving and dislodging cores of unmined material. The cutter elements 28 have cutter bits 36 secured thereto and extending forwardly therefrom.

Boring head 22 extends forwardly from the transmission housing 16 and is positioned rearwardly of

boring heads

18 and 20. The central boring head 22 has radially extending cutter elements 38 and an axial core burster 40. With this arrangement, the boring heads 18, 20 and 22 are arranged to cut a plurality of contiguous bores in the mine face and dislodge the coal therefrom. The frame 12 has a longitudinally extending passageway 42 in which there is positioned an endless conveyor 44. The material dislodged by the boring heads 18, 20 and 22 is directed toward the central passageway 42 and is conveyed rearwardly on the mining machine 10 and discharged into a suitable receiver.

Positioned behind the boring heads 20 and 22 and extending horizontally of the frame 12 are trimmer bars or drum cutters generally designated by the numerals 4.6 and 48. The upper drum cutter 46 is rotatably supported on a horizontally extending support 50 (FIGURE 3). Secured to the front face of the transmission housing 16 are a pair of cylinders 52 one of which is shown in FIG- URE 1. Extending upwardly from the cylinders 52 is a shaft or rod 54 that is connected to the drum cutter support 50. The rod 54 is telescopically arranged within the cylinder 52 and provides a means to adjust the drum cutter 46 vertically relative to the frame 12. The bottom drum cutter 48 is similarly connected to the transmission housing 16. With this arrangement, the trimmer bars 46 and 48 are movable vertically relative to the frame 12 to various preselected positions. The adjustable feature of the drum cutters 46 and 48 permits the drum cutters to dislodge the depending and upstanding cusps that remain between the bores formed by the boring heads 18, 20 and 22 and to form an elongated elliptical bore in the mine face that has a horizontal bottom surface and a horizontal top surface substantially tangential to the bores formed by the

boring heads

18 and 20.

The driving connections between the drive motors 24. and the

boring heads

18, 20 and 22 are illustrated in FIGURE 4. The transmission housing 16 has a front wall 56 in which the shafts 58, 60 and 62 associated with the

boring heads

18, 20 and 22 are journaled. The pair of motors 24. are connected to input shafts 64 and 66 journaled in the rear wall 68 of transmission housing 16. Input shaft 64 has gear 70 splined thereto and meshing with gear 72 on shaft 74. Gear 76 on shaft 74 meshes with gear 78 on shaft 80. The shaft 80 has a gear 82 that meshes with and drives gears 84 and 86 on shafts 88 and 90. Connected to shaft 88 is a spur gear 92 that drives a gear 94 secured to rotor shaft 58. Similarly, shaft has a spur gear 96 secured thereto that is drivingly connected to gear 98 through an intermediate gear 100. Gear 98 is secured to rotor shaft 62 so that the rotor 22 connected to shaft 62 is driven by means of gear 98.

The other drive motor 24 is connected to the input shaft 66. The shaft 66 has a spur gear 102 that meshes with spur gear 194 on shaft 106. The shaft 106 in turn has a gear 108 secured thereto and in meshing relation with gear 110 on parallel shaft 112. Shaft 112 has a gear 114 thereon that meshes with gear 116 on shaft 118. A gear 120 on shaft 118 meshes with gear 122 secured to the rotor shaft 60 so that the rotor shaft 60 is driven by the motor 24. connected to input shaft 66. With this arrangement, the boring heads 18, 20 and 22 are driven by the drive motors 24 through the above described gearing arrangement.

The transmission housing 16 has a shaft 124' journaled therein with a spur gear 126 secured thereto and in meshing relation with the gear 94 connected to the shaft 58 of boring head 18. The shaft 124 provides a mechanical driving connection from the gearing within the transmission 16 that drives the drum cutters 46 and 48. Thus, when the

boring heads

18, 20 and 22 are rotating, the drum cutters 46 and 48 are driven through the gears 94 and 126.

Referring to FIGURE 5 the shaft 124 and gear 126 are illustrated in side elevation. The shaft 124 is connected through a flexible coupling 128 to an input shaft 130 for the auxiliary transmission mechanism within the auxiliary transmission housing 132. Extending forwardly from the auxiliary transmission housing 132 are a pair of

output shafts

134 and 136. The

output shafts

134 and 136 are drivingly connected to the input shaft 130 through gearing within the transmission housing 132. The transmission housing 132 is suitably secured to the side wall of the main transmission housing 16 and rotatably supports the input shaft 130 in bearings 138. A gear 140 is secured to input shaft 130 and is rotatable therewith. The gear 140 meshes with a gear 142 mounted on an idler shaft 144. A tubular shaft 146 is journaled in the auxiliary transmission housing 132 and is rotatably supported on

bearings

148 and 150. The tubular shaft has an externally toothed gear 152 formed thereon that meshes with spur gear 142. With this arrangement, rotation of input shaft 130 is transmitted through gears 140,

142 and 152 to tubular shaft 146. The tubular shaft 146 has an internal bore 156 in which there is coaxially positioned shaft 158. The shaft 158 is suitably dimensioned to be rotatable relative to tubular shaft 146. The tubular shaft 146 has a flange member 160 secured thereto adjacent the rear end portion externally of the auxiliary transmission housing 132. The flange member 160 has a plurality of longitudinal passageways 162 extending therethrough. Suitable means are provided such as splines 164 to nonrotatably secure the radial flange 160 to the tubular shaft 146.

The coaxially positioned inner shaft 158 has an annular radial flange 166 nonrotatably secured to the end portion 168 externally of the auxiliary transmission housing 132. Suitable splines 170 are provided on shaft 158 to nonrotatably secure the annular flange 166 thereto. A cap member 172 is secured to the shaft 158 to maintain the

flanges

160 and 166 positioned in abutting relation to each other as is illustrated in FIGURE 5. The annular flange 166 has a plurality of passageways 174 therethrough which are arranged to be aligned with passageways 162 in radial flange 160. Shear pins 176 extend through aligned passageways 162 and 17.4 to connect the tubular shaft 146 to the coaxially positioned inner shaft 158. The output shaft 136 is splined to the shaft 158 so that output shaft 136 is driven by shaft 1S8.With this arrangement, rotation of tubular shaft 156 is transmitted through flange 160, shear pins 176 to flange 166 and from flange 166 to the inner shaft 158. The upper output shaft 134 is similarly connected to the input shaft 130 through similar gearing and similar reference numerals designate similar parts.

An extensible telescopic shaft 178 is connected to output shaft 134 through universal connecting means 180. Similarly, a lower telescopic shaft 182 is connected to the lower output shaft 136 through a universal connection 184.

As illustrated in FIGURES 2 and 3, the upper drum cutter support member 50 has a transfer case generally designated by the numeral 186 secured thereto and extending laterally therefrom. The transfer case 186 has a vertical portion 188 and a horizontal portion 190. The horizontal portion 190 has a shaft 192 rotatably supported therein on bearings 194. The shaft 192 is connected to the telescopic shaft 178 through a universal connecting means 196. With this arrangement, the rotation of output shaft -134 is transmitted through telescopic shaft 178 to the shaft 192 journaled in transfer case 186. Secured to and rotatable with the shaft 192 is a bevel gear 198. The bevel gear 198 meshes with a bevel gear 200 secured to a shaft 202 that extends into the transfer case vertical portion 188. Within the transfer case vertical portion 188 suitable gearing is provided to connect shaft 200 to the horizontally extending upper drum cutter 46 so that rotation of output shaft 134 drives the upper drum cutter 46.

There is illustrated in detail in FIGURE 6 the manner in which the lower output shaft 136 is connected to the lower drum cutter 48. Referring to FIGURES 5 and 6 there is a lower transfer case 204 that has a vertical section 206 connected to the lower drum cutter support and a horizontal section 208. Within the horizontal section 208 there is a shaft 210 rotatably mounted with an end portion 212 extending rearwardly therefrom. The shaft end portion 212 is connected through a universal connecting means 214 to the telescopic shaft 182. With this arrangement, rotation of the lower output shaft 136 is transmitted through telescopic shaft 182 to the shaft 210 within transfer case 204. There is a bevel gear 216 nonrotatably secured to shaft 210- that meshes with a bevel gear 218 mounted on shaft 220. The shaft 220 is journaled in the transfer case vertical portion 206 and has a spur gear 222 nonrotatably secured thereto. An idler shaft 224 is nonrotatably supported in the transfer case vertical portion 206 and has a gear 226 secured thereto and in meshing relation with the gear 222. The lower drum cutter 48 is nonrotatably secured to a shaft 228 by means of splines 230 or the like. The shaft 228 is journaled in the transfer case vertical portion 206 and has a spur gear portion 232 that meshes with the spur gear 26. With this arrangement, rotation of output shaft 136 is transmitted to the lower drum cutter 48 through the above described gearing and shafting. The other end of the lower drum cutter 48 has a shaft 234 secured thereto. The shaft 234 is mounted on hearing 236 within a housing 238 that is secured to the lower drum cutter support 240.

It should be noted that bevel gears 216 and 198 provide rotation to the respective drum cutters in the opposite directions. For example, the upper drum cutter 46 is arranged to rotate in the direction indicated by the arrow in FIGURE 1 and move the dislodged coal downwardly toward the conveyor 44. Similarly, the lower drum cutter 48 is arranged to rotate in the opposite direction and move the dislodged coal upwardly into the conveyor 44. The drum cutters 46 and 48 have a plurality of cutter bits 242 arranged thereon in the configuration illustrated in FIGURE 1 to direct the dislodged coal toward the center of the mining machine and the longitudinal passageway 42 in which conveyor 44 is positioned.

With the above described boring machine there is provided a mechanical drive for the upper and lower drum cutters 46 and 48. The drum cutters 46 and 48 are driven through suitable driving connections from the gearing in the main transmission. The shear pins 176 extending through the

passageways

162 and 174 in the respective flange members and 166 provide a disengaging means to disconect either the upper or lower drum cutters 46 and 48 from the mechanical drive means, The shear pins may be quickly replaced without moving the mining machine rearwardly to gain access to the front portion thereof. As is illustrated in FIGURES 2 and 3, the

flange portions

160 and 166 nonrotatably secured to each other by shear pins 176 are positioned along the side of the mining machine 10 and rearwardly of the drum cutters 46 and 48. When either one or both of the drum cutters are disconected from the drive means by the breakage or shearing of shear pins 176 due to the forces exerted on the drive connections excluding the shear strength of the shear pins, the operator can realign the passageways in the

flange portions

160 and 166 and insert new shear pins 176 to again drivingly connect the

flanges

160 and 166 to each other. When this arrangement, the shear pins serve as a safety means to limit the forces exerted on the driving connections between the drive motors and the drums cutters.

According to the provisions of the patent statutes, I have explained the principle, preferred construction, and mode of operation of my invention and have illustrated and described what I now consider to represent its best embodiment. However, I desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

I claim:

1. In a boring type mining machine the combination comprising,

a mobile body with a plurality of drive motors thereon and a transmission housing extending forwardly therefrom,

a plurality of boring heads journaled on parallel axes extending forwardly from said transmission housing,

driving connections within said transmission housing drivingly connecting said drive motors to said boring heads so that said boring heads are operable to cut a plurality of contiguous bores in the mine face,

horizontally extending rotary trimmer means positioned rearwardly of said boring heads, said rotary trimmer means arranged to dislodge the cusps of unmined material left between said contiguous bores formed by said boring heads,

drive means connecting said rotary trimmer means to said drive motors so that said rotary trimmer means and said boring heads are driven by said drive motors, and

disconnect means positioned laterally of said transmission housing to provide access thereto from the side of said mining machine, said disconnect means formin g a part of said drive means and being operable to disconnect said rotary trimmer means from said drive motors when said drive means is subjected to forces that exceed preselected forces.

2. A boring type mining machine as set forth in claim 1 in which said horizontally extending rotary trimmer means includes,

an upper drum cutter operable to dislodge the depending cusps of unmined material left between said contiguous bores, and

a lower drum cutter operable to dislodge the upstanding cusps of unmined material left between said contiguous bores.

3. A boring type mining machine as set forth in claim 2 which includes,

means to adjust said drum cutters in a vertical plane to regulate the distance therebetween and form in conjunction with said boring heads an elongated elliptical bore in the mine face.

7 4. A boring type mining machine as set forth in claim 1 in which said drive means conecting said rotary trimmer means to said drive motors includes an auxiliary transmission positioned along the side of said main transmission housing,

said auxiliary transmission having an input means and an output means, said input means drivingly connected to said drive motors and said output means drivingly connected to said rotary trimmer means, driving connections Within said auxiliary transmission connecting said input means and said output means, and said disconnect means positioned externally of said auxiliary transmission housing and laterally of said transmission housing to provide access thereto from i the side portion of said mining machine, said disconnect means arranged to disconnect the driving connections within said auxiliary transmission when said driving connections are subjected to forces in excess of preselected forces.

5. A boring type mining machine as set forth in claim 1 in which said drive means includes,

a drive shaft driven by said drive motors, said drive shaft having a radially extending flange portion with longitudinal passageways therethrough,

a driven shaft coaxially positioned relative to said drive shaft, said driven shaft having a radially extending flange portion with longitudinal passageways therethrough, I

said flange portions positioned in abutting relation with each other with said respective passageways aligned with each other, and laterally of said transmission housing, and

pin means positioned in said passageways and drivingly connecting said driven shaft to said drive shaft, said pin means construction to shear when said drive means is subjected to forces in excess of preselected forces and thereby disconnect said driven shaft from said drive shaft.

6. A boring type mining machine as set forth in claim 1 in which said drive means connecting said rotary trimmer means to said drive motors includes an auxiliary transmission positioned along the side of said main transmission housing,

said auxiliary transmission having an input means and an output means, said input means drivingly connected to said drive motors and said output means drivingly connected to said rot-ary trimmer means,

driving connections within said auxiliary transmission including a first shaft driven by said input means and a second shaft driven by said first shaft, said driving connections connecting said input means and said output means, and

pin means rotatably connecting said first shaft to said second shaft, said pin means constructed to shear when said drive means is subjected to forces in excess of preselected forces and thereby disconnect said auxiliary transmission output means from said input means.

7. In a boring type mining machine as set forth in claim 2 in which said drive means connecting said upper drum cutter and lower drum cutter to said drive motors includes an auxiliary transmission positioned along the side of said main transmission housing,

said auxiliary transmission having an input shaft and a pair of output shafts, said input shaft drivingly connected to said drive motors and said pair of output shafts drivingly connected to said upper and lower drum cutters,

driving connections within said auxiliary transmission connecting said input shaft to both of said output shafts, and

separate disconnect means positioned externally of said auxiliary transmission housing and arranged to disconnect said input shaft from said respective output shafts when said driving connections between said drum cutters and said input shaft are subjected to forces in excess of preselected forces.

8. A boring type mining machine as set forth in claim 7 in which said driving connections within said auxiliary transmission include,

a first shaft driven by said input shaft and a second shaft driven by said first shaft, said second shaft drivingly connected to one of said output shafts,

said driving connections within said auxiliary transmission further including a third shaft driven by said input shaft and a fourth shaft drivingly connected to said other output shaft, and

separate disconnect means including separate pin means rotatably connecting said first shaft to said second shaft and said third shaft to said fourth shaft, said separate pin means arranged to shear when said drive means is subjected to forces in excess of preselected forces to thereby disconnect said input shaft from said respective output shafts.

9. A boring type mining machine as set forth in claim 3 in which said drive means connecting said upper drum cutter and lower drum cutter to said drive motors ineludes an auxiliary transmission positioned along the side of said main transmission housing,

driving connections within said auxiliary transmission connecting said input shaft to both of said output shafts,

separate disconnect means positioned externally of said auxiliary transmission housing and arranged to disconnect said input shaft from said respective output shafts when said driving connections between said drum cutters and said input shaft are subjected to forces in excess of preselected forces, and

telescopic shafts connecting said upper drum cutter and said lower drum cutter to said respective output shafts, said telescopic shafts arranged to permit movement of said drum cutters in a vertical plane while maintaining said drum cutters drivingly connected to said respective output shafts.

References Cited UNITED STATES PATENTS 2,823,023 2/1958 Hlinsky 299-59 X 2,866,626 12/1958 Moon 299-59 X 2,868,528 1/1959 Cartlidge et al 29959 ERNEST R. PURSER, Primary Examiner.