Abstract:
A compact hoist with a central hoist housing and an enclosed transmission located opposite a motor. The output shaft, of the motor, is guided coaxially through a transmission output shaft that is hollow and supports a sprocket wheel, or similar device, and receives power from the transmission. The hoist is particularly easy and economical to assemble, service and repair, and is flexible when in use. In a preferred embodiment, the motor shaft is mounted in a transmission cover opposite the motor and the transmission-output shaft is mounted, on one side in the wall of the hoist housing, and on the other side in an end plate of the motor. That configuration makes the invention particularly suitable for automatic assembly.

Description:
This application is a continuation of U.S. application Ser. No. 07/505,262, filed on Apr. 4, 1990, now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a compact hoist that is configured for convenient assembly, disassembly and servicing and, more particularly, to a hoist having a sprocket, or other hoist wheel, that can be installed and removed without assembly and disassembly of the hoist transmission. Further, the present invention relates to a compact hoist that can employ a variety of differently configured sprockets or other hoist wheels. 
     2. Background of the Information 
     German Laid Open Patent No. 33 30 528 discloses an electrically operated compact chain hoist. The sprocket wheel of the hoist is located between the motor and the transmission of the hoist. With this design, the motor shaft and the drive shaft are coaxially positioned wherein the rapidly rotating outer drive shaft is powered by the slowly rotating inner output shaft. Although that design provides a good weight balance, there are, still, significant disadvantages. Some of the disadvantages include the lack of ease of assembly, lack of ease of maintenance, high replacement part costs for the parts subject to wear, and extremely low flexibility since the hoist cannot be equipped with winding devices other than a standard sprocket wheel or with larger sprocket wheel variants. 
     With that hoist, the sprocket wheel, which frequently becomes worn when subjected to intensive use, can only be replaced after dismantling the transmission and removing the motor. The transmission fluid must also be drained and then replaced. 
     When the sprocket wheel becomes worn, which occurs rapidly if the hoist is not lubricated regularly, the entire output shaft, which is designed as a single piece with the sprocket wheel, must be replaced. Since the housing acts as a chain guide and, therefore, narrowly encloses the sprocket wheel, varying designs of the sprocket wheel, e.g. sprocket wheels with a higher number of teeth or an increased diameter, or even the installation of cable drums which wind the cable in several layers, are not possible. 
     OBJECT OF THE INVENTION 
     One object of the invention, therefore, is to provide a hoist that eliminates these disadvantages. Other objects are to provide a compact hoist which is easy and economical to operate, install, assemble, service and repair, that is flexible in use and that is suitable for automatic assembly. 
     SUMMARY OF THE INVENTION 
     These objects are achieved by mounting the motor shaft, of the hoist, in the transmission cover, opposite the motor, and mounting one side of the transmission output shaft in the transmission-side wall of the hoist housing and the other side of the shaft on an end plate of the motor. Neither the motor nor the transmission need to be opened to remove the sprocket wheel. Further, because of the large assembly opening provided when the motor is removed, the sprocket wheel and/or the other winding device can be replaced without removing any additional parts. Only four motor flange bolts need to be removed to remove the sprocket. The time required to replace a sprocket wheel, with a bearing arrangement of the present invention, is only approximately 7 minutes while, on other chain hoists of the prior art, such an operation takes approximately 1/2 to 1 hour. 
     In another embodiment of the present invention, the center opening of the hoist housing is configured to mate with an end plate of the motor. The opening is larger than the diameter of the sprocket wheel or other winding device. Through this opening the sprocket wheel or other winding devices, that are mounted with a close sliding fit on an involute gearing with head centering of the transmission-output shaft, can be installed and removed. 
     In another embodiment of the invention, the hoist has an opening on the top that can be closed by a cover. Hoisting apparatus can, optionally, be routed outside the housing through that opening. On the outside of the transmission cover, there are, preferably, fastening surfaces for control elements such as terminal strips, flat connector blocks, rails for fastening protective elements, pulse generators and/or limit switches. Moreover, the hoist housing has various holes to accommodate the bolting-on of one of several sizes of motor. That results in a high degree of flexibility of output, i.e. load-carrying capacity and hoisting speed. Additional holes on the side of the hoist housing also make possible a lateral flange mounting of the hoist, which is advantageous in stationary operation or under certain installation conditions. 
     The hoist of the present invention, when the hoisting apparatus exits from the bottom, also has an attachment surface for the optional mounting of various guidance elements for the hoisting apparatus. 
     In still another embodiment of the present invention, the housing cover has insertion, or plug-in, openings in which various inserts for the electrical equipment installation can be form-fitted in any desired arrangement. Such electrical equipment may include power cables of various sizes, control cables including strain relief devices, plug-and-socket connections and limit switches. The system also provides for the lateral insertion of electrical equipment that is prefabricated and tested outside the hoist. 
     For the simple, direct mounting of limit switches for the hoist, holes are provided, on the underside of the hoist housing, into which fastening bolts can be directly inserted. As a result of the installation of direct-switching switch elements in the enclosed electrical equipment chamber, in addition to a high degree of electrical protection, it also becomes economically possible to provide a high degree of mechanical protection. With the present invention, externally-mounted levers actuate the direct-action switch elements via sealed rubber membranes. Such an arrangement makes it possible to eliminate the need for cable ducts, for external switches and the electrical control equipment can be installed completely pre-wired. The hoist housing also has a lateral recess in the vicinity of the exit of the hoisting apparatus, which makes it possible to deflect the hoisting apparatus approximately vertically upward, to get a better overall trolley length. 
     One aspect of the invention resides broadly in a hoist for moving a load. The hoist includes a motor having a first housing, a transmission having a second housing, a motor shaft having a first end, a transmission shaft having a second end and a third end, a wheel defining an external dimension and for being connected to the transmission shaft and a third housing for at least partially enclosing the wheel. The motor shaft is for being connected to the motor and the transmission and for transferring mechanical power from motor to the transmission. The transmission shaft is for being connected to the transmission and for receiving mechanical power from the transmission shaft and the wheel. The wheel receives mechanical power from transmission shaft. The first end of the motor shaft is for being rotatably mounted in the second housing of the transmission. The second end of the transmission shaft is for being rotatably mounted in the third housing. The third end of the transmission shaft is for being rotatably mounted in the first housing of the motor. The third housing defines an opening of a size that is larger than the external dimension of the wheel. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The following Description of the Preferred Embodiments may be better understood when taken in conjunction with the appended drawings in which: 
     FIG. 1 is a side elevational view, partially in section of the present invention; 
     FIG. 2 is another side elevational view, partially in section, of the present invention; 
     FIG. 2a is an exploded side elevational view, partially in section, of the present invention; 
     FIG. 3 is an end view of the present invention; 
     FIG. 4 is a sectional view of the present invention taken along line IV--IV in FIG. 3; 
     FIG. 5 is a top view of a portion of the present invention taken along line V--V in FIG. 3; 
     FIG. 6 is a bottom elevational view of a portion of the present invention and a limit switch installed therein; 
     FIG. 7 is a sectional view of a portion of the present invention taken along line VII--VII in FIG. 6; 
     FIG. 8 is an enlarged sectional view of the rocker switch of the present invention taken along line VIII--VIII of FIG. 6; 
     FIG. 9 is a sectional front elevational view of the present invention suspended by a trolley; 
     FIG. 10 is another sectional front elevational view of the present invention suspended by a trolley; 
     FIGS. 11-14 are side elevational views of the hoisting apparatus guides employed in the present invention; and 
     FIGS. 15-20 show various wheels that may be employed by the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     As shown in FIG. 1, hoist housing 1, suspended by bolts 2, is positioned between motor 11 and transmission section with electrical cover 22. Positioned in hoist housing 1, is transmission-output shaft 14, which is provided for turning interchangeable winding devices. Depending on the users requirements, the winding devices may be any suitable wheel sheave, pulley, or the like, such as standard sprocket wheel 23a, double sprocket wheel 23b, roller chain sprocket wheel 23c, toothed belt roller 23d, flat cable drum 23e or round cable drum 23f, as shown in FIGS. 15 through 20. 
     As shown in FIG. 2, hoist housing 1 has, on one side, housing wall 5, with bearing 6 for transmission output shaft 14, which supports sprocket wheel 23a. The other side of the housing has a large center opening 4, for mating with end plate 12 of motor 11, in which there is bearing 15 of transmission-output shaft 14. Transmission cover 17, which is bolted onto hoist housing 1, supports motor bearing 16 on the transmission-side end of motor shaft 13. As shown in FIG. 3, flange surface 9, of hoist housing 1 and center opening 4, have several threaded holes 7 for the connection of motors of various sizes. Flange surface 9, also, has two fastening holes 8 for the connection of the hoist to a support structure. 
     As shown in FIGS. 2, 4 and 6, hoist housing 1, on the underside, has grooves 10 for the insertion of various guidance elements 28a, 28b, 28c and 28d, that are provided for guiding hoisting apparatus 29. In the embodiment illustrated in FIG. 2, for example, hoisting apparatus 29 is a chain. The hoist housing has opening 30 on the upper side for receiving insert 31 having support screw 32. Insert 31 is employed to prevent hoisting apparatus 29 from escaping from sprocket wheel 23a. Hoist housing 1 defines recess 34, as shown in FIG. 5, for guiding hoisting apparatus 29 as shown in see FIG. 10. 
     Transmission cover 17 has several fastening flanges 25 for control elements 26, which project inward into the electrical equipment space 33. Equipment space 33 is enclosed by electrical cover 22. Transmission cover 17, also, defines insert, or plug-in, openings 10a for receiving cables and inserts 18b. FIG. 2a shows motor 11 removed from hoist housing 1 and sprocket wheel 23a extracted from large, center opening 4. 
     FIGS. 6 through 8 show the components of the limit switch, for upper hook position A and lower hook position B. Bolt 19 is bolted into hoist housing 1. Two-armed lever 20 is supported on one end of bolt 19 and, also, is held by spring 35. Lever 20 actuates switch elements 21. Switch elements 21 are equipped with rubber membranes 24 and are fastened by means of inserts, or plugs, 18b in transmission cover 17. 
     The two levers 20 project, by means of extensions 20a, into holes 3a of rocker switch 3. Rocker switch 3 is held in contact, by springs 35a, with contact surface 3b, as shown in FIG. 8. Switch 3 is supported on guide element 28a, for hoisting apparatus 29, by springs 35a, which are in contact with the heads of bolts 19a. Actuation surfaces 3c, of rocker switch 3, are cambered and facilitate the alternating actuation of the switch elements when switching contacts 36, of hoisting apparatus 29, have moved to the highest or lowest load position. 
     FIG. 9 shows the hoist on a short, overhead trolley, whereby hoisting apparatus 29 is guided from flat rope drum 23e, through upper opening 30, around deflector rollers 37 and lower flange 38, to fixed point 39. 
     In the embodiment illustrated in FIG. 10, the bottom of the hoist housing includes chain deflector element 28c. From that position, hoisting apparatus 29 runs through recess 34, around deflector roller 37a (position shown) to load hook 40. Load hook 40 can be pulled close to the hoist, since starting distances C and L are small. 
     FIGS. 11 through 14 show single chain guide element 28a, double chain guide element 28b, chain deflector element 28c and idler roller element 28d for a flat rope, or belt. 
     In summary, one feature of the invention resides broadly in a compact hoist with a central hoist housing and a enclosed transmission located opposite a motor, with a motor shaft guided coaxially through a transmission output shaft designed as a hollow shaft and supporting a sprocket wheel or similar device leading to the transmission, characterized by the fact that the motor shaft 13 is mounted in a transmission cover 17 opposite the motor 11, and that the transmission drive shaft 14 is mounted on one hand in the wall 5 of the hoist housing 1 and on the other hand in an end plate 12 of the motor 11, and a center opening 4 of the hoist housing 1 for the end plate 12 of the motor 11 is larger than the diameter of the sprocket wheel 23a or of another winding device 23b to 23f. 
     Another feature of the invention resides broadly in a compact hoist, characterized by the fact that the transmission drive shaft 14, at least in the vicinity of the sprocket wheel 23a or of another winding device 23b to 23f and of a motor-side transmission bearing 15, has an involute toothing 16a with head centering and close sliding fit. 
     Yet another feature of the invention resides broadly in a compact hoist, characterized by the fact that the hoist housing 1, on the top, has an opening 30 which can be closed by an insert 31, through which the rope means can optionally exit. 
     A further feature of the invention resides broadly in compact hoist, characterized by the fact that on the outside of the transmission cover 17 there are fastening flanges 25 for control elements 26 such as terminal strips, flat connector blocks, fastening rails. 
     A yet further feature of the invention resides broadly in a compact hoist, characterized by the fact that the hoist housing 1 on the side on which the rope means exit has a connecting surface 27 for the mounting of various guidance elements 28a to 28d for the rope means. 
     Yet another further feature of the invention resides broadly in a compact hoist, characterized by the fact that the hoist housing 1 on the motor side has several threaded holes 7 for the installation of motors of different sizes. 
     An additional feature of the invention resides broadly in a compact hoist, characterized by the fact that the hoist housing 1 has additional fastening holes 8 and a flange surface 9. 
     A yet additional feature of the invention resides broadly in a compact hoist, characterized by the fact that the transmission cover 17 has insertion openings in the bottom to accept various inserts 18a and 18b. 
     A further additional feature of the invention resides broadly in a compact hoist, characterized by the fact that the hoist housing 1 has holes for bolts 19 for the optional mounting of levers 20 for the actuation of electrical switch elements 21, e.g. limit switches. 
     A yet further additional feature of the invention resides broadly in a compact hoist, characterized by the fact that the switch elements 21 for the limit switch functions are located inside an equipment space 33, formed by the transmission cover 17 and an electrical cover 22, and can be actuated from outside via sealed rubber membranes 24 by means of the levers 20. 
     Another further additional feature of the invention resides broadly in a compact hoist, characterized by the fact that the hoist housing 1 has a recess 34 on the side for the feed-through of a deflected rope means. 
     Some examples of involute gears and gear teeth can be found in U.S. Pat. No. 4,896,567, entitled &#34;Planetary Transmission Mechanism and Device of Involute Gears with Complex Minor Tooth Difference&#34;; U.S. Pat. No. 4,833,836, entitled &#34;Process for Grinding a Gear Tooth Blank to Form an Involute Gear Tooth&#34;; U.S. Pat. No. 4,815,239, entitled &#34;Apparatus for Production of Involute Gear Tooth Flanks&#34;; U.S. Pat. No. 4,565,474, entitled &#34;Method of Generating Involute Tooth Forms with a Milling Cutter&#34;; U.S. Pat. No. 4,512,109, entitled &#34;Rolling Gear Apparatus for an Involute Tooth Gear Cutting Machine&#34;; U.S. Pat. No. 4,467,568, entitled &#34;Generating Method for the Chip-Producing Machining of Involute Tooth Flanks with Profile and Longitudinal Corrections&#34;; U.S. Pat. No. 4,322,889, entitled &#34;Testing Apparatus for Involute and Helical Gear Teeth&#34; and U.S. Pat. No. 4,062,125, entitled &#34;Apparatus for Testing the Tooth Flanks of Involute Gearing.&#34; 
     All, or substantially all, of the components and methods of the various embodiments may be used with at least one embodiment or all of the embodiments, if any, described herein. 
     All of the patents, patent applications, and publications recited herein, if any, are hereby incorporated by reference as if set forth in their entirety herein. 
     The details in the patents, patent applications, and publications may be considered to be incorporable, at applicant&#39;s option, into the claims during prosecution as further limitations in the claims to patentably distinguish any amended claims from any applied prior art. 
     The invention as described hereinabove in the context of the preferred embodiment is not to be taken as limited to all of the provided details thereof, since modifications and variations thereof may be made without departing from the spirit and scope of the invention.