US3590522A

US3590522A - Toy track system

Info

Publication number: US3590522A
Application number: US784305A
Authority: US
Inventors: Nobuo Hamano
Original assignee: Tomy Kogyo Co Ltd; YONEZAWA GANGU CO Ltd
Current assignee: Tomy Kogyo Co Ltd; YONEZAWA GANGU CO Ltd
Priority date: 1968-05-10
Filing date: 1968-12-17
Publication date: 1971-07-06
Anticipated expiration: 1988-07-06
Also published as: GB1240140A

Abstract

A toy track system in which an electric motor-driven toy vehicle runs on a pair of continuous conductive rails which are disposed inside a transparent tunnellike cover or dome, said conductive rails being electrically connected to an electric control box which supplies power to said rails for driving the vehicle.

Description

ilnited Mates Patent [72} Inventor Nobuo Hamano Tokyo, Japan [2| Appl. No. 784.305

[22] Filed Dec. 17,1968

[4S] Patented July 6, 197] [731 Assignees Tomy Kogyo Co., Ltd.

Tokyo, Japan; Yonezawa Gangu C0., Ltd. Tokyo, Japan [32] Priority May 10, 1968, May 13, 1968,0et. 14,

[3 3 Japan {3 l 43/38 180. 43/39479 and 43/74894 [54] TOY TRACK SYSTEM 4 Claims, 8 Drawing Figs.

[52] US. Cl 46/231 [51} lint. Cl A63h 33/26 [50] Field oiSearch 46/l,43, 231. 243, 68, 201, 202, 216; 238/l0; 273/86 [56] References Cited UNITED STATES PATENTS 1,482,636. 2/1924 Fergusson 2.026.181 12/1935 Kennedy 46/243 2,876,952 3/1959 Washabaugh..... 238/10 3.276.393 10/1966 Lewis. 46/243x 3.308.576 3/1967 Nadolnym. 46/243 3,313,242 4 1967 VOC8.......... 46/243x 3,343,793 9/1967 Waser 238/10 3,486,271 12/1969 Feikema 66/243 FOREIGN PATENTS 453.350 11/1927 Germany 238/10 385,036 12/1932 GreatBritain 238/10 Primary Examiner-Louis G. Mancene Assistant Examiner-D. L. Weinhold Attorney-McGlew and Toren ABSTRACT: A toy track system in which an electric motordriven toy vehicle runs on a pair of continuous conductive rails which are disposed inside a transparent tunnellike cover or dome, said conductive rails being electrically connected to an electric control box which supplies power to said rails for driving the vehicle.

TOY TRACK SYSTEM SUMMARY OFTHE INVENTION This invention relates to a toy and more particularly to a new and useful toy railroad or track system comprising. in combination, a domed continuous track and an electric motor-driven toy vehicle, The railroad is arranged in such a way that an electric motor-dirven toy vehicle is adapted to run on a pair of conductive rail members disposed within a transparent dome or semicylindrical housing, said rail members being electrically connected to an electric control box.

A number of toy railroads or track systems have heretofore been proposed. Most of these are usually constructed such that an electrically operated train or vehicle is adapted to run on a more conventional track, such as a pair of conductive rails which is exposed to view. Therefore, they have, in general. the disadvantages of being monotonous in appearance and lacking in attractiveness. it is also pointed put that it is difficult to effect a satisfactory electrical connection between the conductive rail sections and also that the rail sections themselves are difficult to connect.

It is, therefore, one object of the present invention to provide entertainment and amusement for children by avoiding such disadvantages and providing a novel and useful toy electric railroad or track system in which an electric motor-driven toy vehicle runs on a pair of continuous conductive rail members which are disposed inside a transparent or translucent tunnellilte cover so that the vehicle travelling therethrough can be viewed from the outside through such cover.

it is another object of the present invention is to provide a new and useful toy of the kind stated above which comprises an electrically operated toy vehicle having a miniature bulb emitting light rays, and a transparent or translucent tunnellike cover having a conductive track on which the vehicle is adapted to run, said tunncllilte cover or dome having means for rcfracting and/or reflecting the light rays emitted by said bulb so that the light rays will be diffused in various directions, as the vehicle runs through the continuous dome, to thereby increase socallcd "play value" of the toy.

It is further object of the present invention to provide a new and useful toy electric railroad or track system of the character described above which comprises different shapes of domed electrical rails which can be easily connected together to form any desired shape of a continuous track and which can be perfectly electrically connected to each other.

it is still further object of the present invention to provide a new toy railroad or track system of the type set forth above which comprises supporting members and accessory members for use in the formation of a new elevated railroad of modern type.

It is yct another object of the present invention to provide a new toy railroad or track system in which the travelling of an electric motondrivcn toy vehicle can be remotely controlled by manual operation of an electric control box.

The features of the present invention which are believed to be novel are act forth with particularity in the appended claims. The present invention, both as to its organization and manner of operation, together with further objects and advantages thercof, may best be understood by reference to the following description, taken in connection with the accompanying drawings in which like reference characters refer to like elements.

in the drawings:

FIG. 1 is a perspective view of one embodiment, as a whole, of the present invention;

FIG. 2 is a side view of an electrically operated toy vehicle in its state of being set on a pair of conductive rails in a semicylindrical dome traclt section;

FIG. 3 is a front view of FIG. ll;

FIG. d is a rear view of FIG. 3;

FIG. 5 is a plan view of the toy vchiclc shown in FIG. 2.;

Fifi. d is a bottom view of the toy vehicle shown in FIG. 2,;

FIG. 7 IS a perspective view of a couple of partly cut away semicylindrical dome track sections in the separate state, illustrating the joint portions thereof; and

FIG. 8 is a bottom view ofa semicylindrical dome track sec On.

Referring to the drawings, a combination constituting a presently preferred embodiment of the present invention, generally designated as X, comprises an electric motor-driven toy vehicle A, a semicylindrical dome railroad track of the endless, closed type, generally designated as B, through which the vehicle A is adapted to travel, and an electric control box C.

As shown in FIG. 1, the closed railroad track B comprises an appropriate number of semicylindrically shaped straight dome track sections 1, an appropriate number of semicylindrically shaped curved dome track sections 2 and an appropriate number of semicylindrically shaped inclined dome track sections 3, all of which being coupled to each other to form an endless, closed semicylindrical dome railroad track B.

The semicylindrical domes or tunnellike covers of the track sections through which said vehicle is adapted to travel are made with a colorless transparent plastics material or a translucent colored plastics material, respectively. Each of the track sections is provided with a plurality of convex lens portions 4 which are spacedly arranged on a dome or semicylindrical housing 5 and also with one or a plurality of grooves 4 which are formed in the outer face of the dome 5 along the longitudinal axis thereof so that the effect of refraction and reflection ofthe lights emitted from a miniature bulb 19 of the travelling vehicle A and passing through the dome 5, especially through the lens portions 4 and the grooves 4- will enhance the interest of the user and playing effects of the toy during its operation.

Each of the

track sections

1, 2 and 3 comprises a substantially semicylindrical housing or dome 5 which serves as a tunnellilte passageway and a pair of stepped base portions 5a and 5b which are both formed integrally with said semicylindrical cover member 5 along the bilateral edges of said cover member 5. Said pair of base portions 5a and 5b have vertical wall portions 5a and 5b and horizontal wall portions 5a" and 5b", respectively. One 5a of the vertical wall portions 5a and 5b has a lug 6 extending longitudinally from one end of said vertical wall portions 5a. On this lug 6 is formed a lateral projection 6' which protrude laterally outwardly from said lug. At the other end of the same vertical wall portion fin, there is formed a tonguelike protrusion 7 which extends longitudinally from the end in parallel with the wall portion 5a and has a small hole 7 formed thcrethrough. Between the cover portion 5 and the protrusion 7 is formed a recess 3 as clearly shown in FIG. 8. Similarly, the other vertical wall portion 512' is provided, at one end thereof, with a lug 9 having a lateral projec tion 9 in the position opposite to the protrusion 7 of said vertical wall 54, and also, at the other end of this vertical wall portion 51:, with a longitudinal protrusion 10 having a small hole 10' formed therethrough and a recess lll.

Within each dome track section .t, 2, 3, there are provided a pair of conductive rails 12c and 12b each being made with an elongated conductive metal sheet or thin strip. These conductive rails 12a and 1212, as a pair, are fixed, at one side thereof, to said vertical wall portions do and db at right angle relative to the wall faces of said vertical wall portions by appropriate fastenings 50 which pass through the horizontal portions 5a" and 5b" and the rails respectively. Preferably, each of the

dome track sections

1, 2 and 3 is formed with a plurality of tonguelike flat lugs So, which project laterally inwardly from upper portion of each of the vertical wall portions 5a and 5b" immediately under the lower face of each of the horizontal portions 54" and 5b" of said base portions, so that the pair of

conductive rails

12a and 12b may be firmly supported on the lugs 50 along said vertical wall portions. The conductive rails 12a and 12.12 are provided with two kinds of contact cars 13 and 1.4 one for one roll, said contact ears each depending downwardly fiom one end of each of said rails along the inner face of each of the vertical walls 50 and 5b and integral with each rail. Of these two kinds of

contact cars

13 and 14, the one 13 which is located along the inner face of each ofthe

lugs

6 and 9 is bent over one free end edge ofsaid lug to extend. for a short distance in the reverse direction, on the external face of each of said vertical walls 5a and 5b. The other 14 of the Contact ears extends on and along the inner face of each of the aforesaid protrusions 7 and 10 up to the other end of each of said protrusions. A through-hole is formed in each of these

contact ears

14 and 14 in the portions corresponding to the small holes 7' and 10' of said protrusions 7 and 10.

Terminal lugs 15a and 15b which are connected to the pair of

conductive rails

12a and 12b of one of the

track sections

1, 2 and 3 protrude laterally outwardly from one side of the track section. Supporting pedestals generally indicated as 16 are used in the event of forming an overhead type" cross railway track or an elevated railway by placing the fabricated dome track sections on the upper surfaces of said pedestals 16. On these pedestals are mounted domelike accessories 16 for decorative purposes.

The toy vehicle A which is adapted to run on the rails in the continuous dome track is provided, in an appropriate part thereof, with an electric motor 17. A wheel axle 17' is supported by the bilateral walls of the chassis of the vehicle for rotation. A pair of

wheels

18 and 18 which are made of a rubber material are fixedly mounted on the ends of the axle 17. A pinion (not shown) is fixedly mounted on the free end of an output shaft (not shown) of said motor. This pinion, in turn, meshes with a crown gear (not shown) which is fixedly mounted onsaid axle 17'. A miniature electric bulb 19 is attached, in an appropriate manner, in the interior of the body of said vehicle A. This body of the vehicle is provided with a cover member 20 which is located at a portion adjacent the electric bulb 19. This cover member of the body of the vehicle is made with a transparent plastics material so that the light rays emitted from this miniature electric bulb will pass through said transparent cover member to illuminate the outside of the vehicle.

A pair of

conductive metal sheets

21 and 21 is fixed to the bottom face of the chassis of said vehicle A. At each of the outer side edges of these two

conductive metal sheets

21 and 21, the portions of these sheets which are located close to said wheels are bent upwardly to form two upwardly projecting contactsZla and 21a. In the foreground of said contacts, there are also formed another pair of upwardly projecting

contacts

21b and 21b by bending portions of said conductive sheets. Immediately above the upper edges of these

latter contacts

21b and 21b, there are formed

winglike members

22 and 22 which project laterally outwardly from the lower portion of the body of said vehicle. Guide members 22' and 22' of the vehicle are fixed to its chassis at its portions immediately under said winglike members In order to set said vehicle A on the

conductive rails

12a and 12b in one of the track sections of the track B in the course of the operation of fabricating the toy of the present invention, it is only necessary to insert said

conductive rails

12a and 12b, as a pair, between said guide members 22 and 22' and the second contact pieces 21b of said vehicle and also between said

wheels

18 and 18 and said

first contact pieces

21a and 21a, whereby said

conductive metal sheets

21 and 21 will be brought into contact with and connected electrically to said

conductive rails

12a and 12b, correctly.

Indicated by C is a conventional electric control box. In the interior of this control box C is housed a dry cell or batteries (not shown) and is also contained a variable resistance (not shown) which is engaged with a contact (not shown) fixed to an operating knob 23. The current controlled regulated by the variable resistance which controls the voltage is led to output terminals (not shown) which are connected to lead

wires

24 and 24 which are provided with

nippers

25 and 25 at the foremost ends thereof, respectively.

The semicylindrical

dome track sections

1, 2 and 3 are connected to each other in the following manner. First, two of the track sections are held close to each other edgewise, each being held at an angle of about 45 as illustrated in FIG. 5, and they are brought closer to each other until the small hole 7' of one of the track sections comes to the position of the lateral projection 6' of the other of said track sections, and also until the small hole 10 is positioned to the lateral projection 9'. Then, these lateral projections 6 and 9' are inserted in the small holes 7' and 10', respectively. Thereafter, these two track sections are swung relative to each other about the lateral projections 6 and 9' serving as the fulcrums until these two track sections are aligned straight relative to each other at the end portions of joint of these two track sections. As a result, the

aforesaid lugs

6 and 9 will fit in said

recesses

8 and 11, while on the other hand the

contact cars

13 and 13 of the

conductive rails

12a and 12b, after said

lugs

6 and 9 have thus been firmly contacted by said

contact ears

13 and 13, are brought into tight contact with the

contact ears

14 and 14 which are located side by side with said protrusions 7 and 10. In this way, these two track sections are coupled firmly to each other. Accordingly, the

conductive rails

12a and 12b of one of said track sections will be brought in tight contact with the corresponding

conductive rails

12a and 12b of the other of the two track sections to produce a positive, electrical connection therebetween. It is to be noted that these dome track sections which constitute the railroad track B can be coupled together without the need of any excessive force such as the force with which to broaden the distance between the inner faces of the

lugs

6 and 9, and this fact eliminates the danger that the lateral projections 6' and 9' or other members and elements of the track sections are broken.

After the

track sections

1, 2 and 3 and the supporting pedestals 16 have been fabricated into an assembly in the manner described above, the input terminals 15a and 1511 which are connected to the

conductive rails

12a and 12b of one of said track sections of the track B are nipped by said

nippers

25 and 25 to electrically connect the

conductive rails

12a and 12b to said control box C. Thereafter, the aforesaid knob 23 of the control box C is turned to close the electric circuit. Whereupon, electric current is allowed to flow through the series circuit formed between the

conductive rails

12a and 12b and the motor 17 and the miniature electric bulb 19 of said vehicle A. As a result, the miniature electric bulb 19 is lighted on and at the same time the motor is actuated. The power of this motor is transmitted, through said pinion and said crown gear, to the mile 17 to drive the

wheels

18 and 18. In this way, the vehicle A with its miniature electric bulb 19 being lighted on is caused to run on the

conductive rails

12a and 12b. It is to be noted that during this travel of the vehicle A, the speed of the running vehicle A and the intensity of brightness of the light of the miniature bulb 19 can be freely controlled as desired by the manual operation of the operating knob 23.

As has been stated, the toy railroad or track system of the present invention is formed by combining, in an appropriate manner, several different kinds of individual transparent dome track sections to each other, each being of the same arrangement with the only exception that they are either curved, straight or inclined to produce said several different kinds. Therefore, a variety of an overhead type cross railroad circuits may be easily fabricated by the use of a desired number of the track sections and the supporting pedestals. In addition, the light rays which are emitted from the miniature electric bulb which is provided in the vehicle adapted to run through the tunnel will be refracted and reflected in various directions during the travel of the vehicle by the transparent dome track, especially by the lens portions and the surfaces of the grooves provided on and in semicylindrical dome. Therefore, the patterns of the light rays which are diffused in various directions as the vehicle runs through the continuous tunnel will lead to the advantage that a greatly enjoyable toy is obtained. Furthermore, the unique arrangement of the toy of the present invention has made it possible to effect a satisfactory electric connection between the conductive rails which has been considered extremely difficult. The disposition of the conductive rails within the track sections in such a way as to be integral with the latter permits the manufacture of the aforesaid respective kinds of track sections at a low cost. Also, to use ornamental accessory members such, for example, as seen on the tops of the toy assembly illustrated in FIG. 1 will increase the attractiveness of the toy. Furthermore, by giving an appropriate color or colors to the individual track sections, there will be obtained a beautiful toy as a whole, and what is more, the effect of the diffusion of light described above will be all the more enhanced. it is needless to say that by the use of a plurality of the toy sets of the present invention, they can be utilized also as a unique and novel racing car set.

It should be noted that the principles of the present invention may be applied to different types of toy track systems and that the devices of the present invention, as heretofore stated, may be used in combination with any suitable track system.

While the particular toy herein shown and described in detail is fully capable of attaining the objects and providing the advantages hereinbefore stated, it is to be understood that it is merely illustrative of the presently preferred embodiment of the invention and that no limitations are intended to the details of construction or design herein shown other than as defined in the appended claims.

I claim:

1. A toy assembly comprising, in combination, a tunnellike closed track composed of a plurality of individual dome track sections each comprising a transparent dome molded from a plastics material and a pair of conductive rail members made with a conductive metal sheet, said conductive rail members being mounted in said dome, each of said track sections having first and second ends connected to the first and second ends, respectively, of the other track sections to form a transparent closed dome track having parallel conductive rails, and an electric motor-driven toy vehicle, said vehicle being adapted to run on said conductive rails in said transparent closed dome track by supplying an electric current to said conductive rails, whereby the state of travel of said vehicle may be viewed from the outside through said transparent dome, and said electric motor-driven toy vehicle is provided with a miniature electric bulb which is mounted therein and is arranged to emit light during the travel of the vehicle through the transparent closed dome track, said dome track having at its dome portion means for diffusing the light emitted from said bulb in various directions to thereby cause the pattern of the light projected upon and passing through said dome portion to be varied during the travel of said vehicle.

2. A toy assembly comprising, in combination, a tunnellike closed track composed of a plurality of individual dome track sections each comprising a transparent dome molded from a plastics material and a pair of conductive rail members made with a conductive metal sheet, said conductive rail members being mounted in said dome, each of said track sections having first and second ends connected to the first and second ends, respectively, of the other track sections to form a transparent closed dome track having parallel conductive rails, and an electric motor-driven toy vehicle, said vehicle being adapted to run on said conductive rails in said transparent closed dome track by supplying an electric current to said conductive rails, whereby the state of travel of said vehicle may be viewed from the outside through said transparent dome, each of said track sections comprises a substantially scmicylindrical cover portion and a pair of stepped base portions which are both formed integrally with said semicylindrical cover portion along the bilateral edges of said cover portion, said base portions having horizontal wall portions and vertical wall portions, respectively each of said horizontal wall portions extending outwardly from the lower end portion of said cover portion, and each of said vertical wall portions depending from the outer edge of each of said horizontal wall portions and having at its ends extensions, respectively, said extensions having a firstjoint means and a second joint means, said first joint means being engageable with the second joint means of the other track sections and said second joint means with the first omt means of others, thereby enabling the track sections to be connected to each other with these joint means.

3. A toy assembly comprising, in combination, a tunnellilte closed track composed of a plurality of individual dome track sections each comprising a transparent dome molded from a plastics material and a pair of conductive rail members made with a conductive metal sheet, said conductive rail members being mounted in said dome, each of said track sections hav ing first and second ends connected to the first and second ends, respectively, of the other track sections to form a transparent closed dome track having parallel conductive rails, and an electric motor-driven toy vehicle, said vehicle being adapted to run on said conductive rails in said transparent closed dome track by supplying an electric current to said conductive rails, whereby the state of travel of said vehicle may be viewed from the outside through said transparent dome, each of said track sections comprises a substantially semicylindrical cover portion and a pair of stepped base portions which are both formed integrally with said semicylinds'ical cover portion along the bilateral edges of said cover portion, said base portions having horizontal wall portions and vertical wall portions, respectively, each of said horizontal wall portions extending outwardly from the lower end portion of said cover portion, and each of said vertical wall portions depending from the outer edge of each of said horizontal wall portions and having at its ends extensions with joint means, respectively, said extensions having a first electric contact means and a second electric contact means, respectively, said first contact means being adapted to contact the second contact means of the other track sections and said second contact means with the first contact means of the others, the first and second contacts of the extensions of one of said vertical wall portions being integral with one of said conductive rail members, and the first and second contacts of the extensions of the other vertical wall portion being integral with the other conductive rail member, whereby each of said conductive rail members is electrically connected to the corresponding conductive rail members of the other track sections when fabricated together with said joint means.

4. A toy assembly comprising, in combination, a tunnellilte closed track composed of a plurality of individual dome traclt sections each comprising a transparent dome molded from a plastics material and a pair of conductive rail members made with a conductive metal sheet, said conductive rail members being mounted in said dome, each of said track sections having first and second ends'connected to the first and second ends, respectively, of the other track sections to form a trans parent closed dome track having parallel conductive rails, and an electric motor-driven toy vehicle, said vehicle being adapted to run on said conductive rails in said transparent closed dome track by supplying an electric current to said conductive rails, whereby the state of travel or" said vehicle may be viewed from the outside through said transparent dome, said conductive rail members are made with an elongated conductive metal sheet, respectively, and, as a pair, are fixed, at one side thereof, to the vertical wall portions constituting a portion of the stepped base portions which are both formed integrally with a semicylindri-cal cover portion of the track section along the bilateral edges of said cover portion, at right angle relative to the wall faces of said vertical wall portions by appropriate means.

Claims

2. A toy assembly comprising, in combination, a tunnellike closed track composed of a plurality of individual dome track sections each comprising a transparent dome molded from a plastics material and a pair of conductive rail members made with a conductive metal sheet, said conductive rail members being mounted in said dome, each of said track sections having first and second ends connected to the first and second ends, respectively, of the other track sections to form a transparent closed dome track having parallel conductive rails, and an electric motor-driven toy vehicle, said vehicle being adapted to run on said conductive rails in said transparent closed dome track by supplying an electric current to said conductive rails, whereby the state of travel of said vehicle may be viewed from the outside through said transparent dome, each of said track sections comprises a substantially semicylindrical cover portion and a pair of stepped base portions which are both formed integrally with said semicylindrical cover portion along the bilateral edges of said cover portion, said base portions having horizontal wall portions and vertical wall portions, respectively each of said horizontal wall portions extending outwardly from the lower end portion of said cover portion, and each of said vertical wall portions depending from the outer edge of each of said horizontal wall portions and having at its ends extensions, respectively, said extensions having a first joint means and a second joint means, said first joint means being engageable with the second joint means of the other track sections and said second joint means with the first joint means of others, thereby enabling the track sections to be connected to each other with these joint means.

3. A toy assembly comprising, in combination, a tunnellike closed track composed of a plurality of individual dome track sections each comprising a transparent dome molded from a plastics material and a pair of conductive rail members made with a conductive metal sheet, said conductive rail members being mounted in said dome, each of said track sections having first and second ends connected to the first and second ends, respectively, of the other track sections to form a transparent closed dome track having parallel conductive rails, and an electric motor-driven toy vehicle, said vehicle being adapted to run on saiD conductive rails in said transparent closed dome track by supplying an electric current to said conductive rails, whereby the state of travel of said vehicle may be viewed from the outside through said transparent dome, each of said track sections comprises a substantially semicylindrical cover portion and a pair of stepped base portions which are both formed integrally with said semicylindrical cover portion along the bilateral edges of said cover portion, said base portions having horizontal wall portions and vertical wall portions, respectively, each of said horizontal wall portions extending outwardly from the lower end portion of said cover portion, and each of said vertical wall portions depending from the outer edge of each of said horizontal wall portions and having at its ends extensions with joint means, respectively, said extensions having a first electric contact means and a second electric contact means, respectively, said first contact means being adapted to contact the second contact means of the other track sections and said second contact means with the first contact means of the others, the first and second contacts of the extensions of one of said vertical wall portions being integral with one of said conductive rail members, and the first and second contacts of the extensions of the other vertical wall portion being integral with the other conductive rail member, whereby each of said conductive rail members is electrically connected to the corresponding conductive rail members of the other track sections when fabricated together with said joint means.

4. A toy assembly comprising, in combination, a tunnellike closed track composed of a plurality of individual dome track sections each comprising a transparent dome molded from a plastics material and a pair of conductive rail members made with a conductive metal sheet, said conductive rail members being mounted in said dome, each of said track sections having first and second ends connected to the first and second ends, respectively, of the other track sections to form a transparent closed dome track having parallel conductive rails, and an electric motor-driven toy vehicle, said vehicle being adapted to run on said conductive rails in said transparent closed dome track by supplying an electric current to said conductive rails, whereby the state of travel of said vehicle may be viewed from the outside through said transparent dome, said conductive rail members are made with an elongated conductive metal sheet, respectively, and, as a pair, are fixed, at one side thereof, to the vertical wall portions constituting a portion of the stepped base portions which are both formed integrally with a semicylindrical cover portion of the track section along the bilateral edges of said cover portion, at right angle relative to the wall faces of said vertical wall portions by appropriate means.