CA2043859A1 - Apparatus for irradiating an ultraviolet light-curable liquid coating applied on a floor - Google Patents

Apparatus for irradiating an ultraviolet light-curable liquid coating applied on a floor

Info

Publication number
CA2043859A1
CA2043859A1 CA 2043859 CA2043859A CA2043859A1 CA 2043859 A1 CA2043859 A1 CA 2043859A1 CA 2043859 CA2043859 CA 2043859 CA 2043859 A CA2043859 A CA 2043859A CA 2043859 A1 CA2043859 A1 CA 2043859A1
Authority
CA
Canada
Prior art keywords
floor
irradiation module
lamp
light
reflector
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
CA 2043859
Other languages
French (fr)
Inventor
Raynald Perron
Rene Bazin
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Priority to CA 2043859 priority Critical patent/CA2043859A1/en
Publication of CA2043859A1 publication Critical patent/CA2043859A1/en
Abandoned legal-status Critical Current

Links

Landscapes

  • Application Of Or Painting With Fluid Materials (AREA)

Abstract

ABSTRACT OF THE DISCLOSURE

The apparatus, for irradiating an ultraviolet light-curable liquid coating applied on a floor, comprises a wheeled body and an irradiation module. This irradiation module generates ultraviolet light projected onto the floor to cure and harden the liquid coating. It is mounted on the wheeled body through a mechanism structured to move it laterally in either direction in order to irradiate the ultraviolet light-curable coating applied on floor portions difficult to reach. A casing contains an ultraviolet light-generating lamp and a reflector, and another mechanism tilts this casing in order to project the ultraviolet light on floor portions of which the access is difficult. The wheeled body is supported by a set of four swivel casters and can therefore be easily displaced in any direction.

Description

20438~9 APPAP~TUS FOR IRRADIATING AN ULTRAVIOLET

LIGHT-CURABLE LIOUID COATING APPLIED ON A FLOOR

BACKGROUND OF THE INVENTION

1. Field of the invention-The present invention relates to an apparatus for irradiating a liquid coating applied on a floor with ultraviolet light in order to cure and harden this coating.
2. Brief description of the prior art:

United States patent N 4,241,255 granted to Sugiyama et al. on December 23, 1980, describes an ultraviolet ray projector for irradiating a light-curable paint, such as various resin coating compositions, applied on a floor in order to harden it.

The projector of United States patent N
4,241,255 comprises a wheeled truck carrying a casing containing a tubular mercury lamp and a reflector.
The casing is elongated and can be mounted on the wheeled truck longitudinally or transversely depending on the desired width of irradiation.

20~3859 A drawback of the prior art ultraviolet ray projector is its incapacity to irradiate the portions of floor of which the access is difficult.

OBJECTS OF THE INVENTION

An object of the present invention is therefore to eliminate the above discussed drawback of the prior art.

Another object of the invention is an apparatus comprising a wheeled body, and an irradiation module that can be moved with respect to the wheeled body in order to irradiate the portions of floor of which the access is difficult.

A further object of the subject invention is an apparatus comprising a lamp and reflector assembly that can be tilted in order to irradiate portions of floor difficult to reach.

SUMMARY OF THE INVENTION

According to the present invention, there is provided an apparatus for irradiating a light-curable liquid coating applied on a floor, comprisingta) a wheeled body displaceable onto the floor, and (b) an irradiation module for generating light which is projected onto the floor to thereby irradiate the 20~38~9 light-curable liquid coating, this generated light being of course capable of curing this coating. The irradiation module is mounted on the wheeled body through a mechanism capable of moving the module with respect to the body.

As the irradiation module can be moved with respect to the wheeled body, the light-curable coating applied on portions of the floor difficult to reach can be easily irradiated.

In accordance with a preferred embodiment of the invention, the coating is an ultraviolet light-curable liquid coating and the generated light comprises ultraviolet light.

In accordance with other preferred embodiments of the invention, the irradiation module comprises a light-generating lamp, a reflector for reflecting light generated by the lamp, a casing containing the lamp and the reflector and having a bottom opening through which the light irradiates the coating, a mechanism for tilting the casing, and a housing in which the casing is disposed, this housing including a vertical wall provided with a lower flap that can be pivoted to enable, when the casing is tilted, the light from the lamp to irradiate portions of floor of which the access is difficult.

According to a further preferred embodiment of the present invention, the wheeled body comprises a plurality of swivel casters whereby it can be easily displaced in any direction.

20~3859 In accordance with other further preferred embodiments of the subject invention, the mechanism comprises ta) a track system mounted on the wheeled body, supporting the irradiation module, and along which the latter module moves transversely in either direction, (b) an elongated toothed rack fixedly mounted on the irradiation module and extending generally parallel to the track system, (c) a toothed wheel meshed with the toothed rack and mounted on a driving shaft rotatable by an electric motor disposed on the wheeled body, whereby rotation of the driving shaft by the motor rotates the toothed wheel meshed with the rack to move the irradiation module along the track system.
The electric motor is advantageously reversible to move the irradiation module along the track system in the two opposite directions.

The objects, advantages and other features of the present invention will become more apparent upon reading of the following non restrictive description of a preferred embodiment thereof, given by way of example only with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE D~AWINGS

In the appended drawings:

20~38~

Figure 1 is a perspective view of an apparatus in accordance with the present invention, for irradiating an ultraviolet light-curable liquid coating applied on a floor;

Figure 2 is a front, cross sectional and elevational view of the irradiation module of the apparatus of Figure l;

Figure 3 is a side elevational view, partially cross sectional, of the apparatus of Figure l;

Figure 4 is a front elevational view of the apparatus of Figure l;

Figure 5 is a front elevational view, partially cross sectional, of the apparatus of Figure 1; and Figure 6 is a side, cross sectional and elevational view of the irradiation module of the apparatus of Figure 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In Figure 1 the appended drawings, the apparatus in accordance with the present invention for irradiating an ultraviolet light-curable liquid coating applied on the surface of a floor in order to cure and harden this coating, is generally identified ., ' ~ ' ~ '.
-. j . .

6 204~8~9 by the reference numeral 1. It comprises a wheeledbody 2a and an irradiation module 2b including a front housing 3 that can be moved horizontally and laterally in either direction with respect to the body 2a.

As shown in Figure 3, the coating 54 to be cured and hardened can be applied for example onto a wooden floor 90, although other types of floor surface can be coated and treated in accordance with the present invention. The liquid coating 54 is ultraviolet light-curable and can be constituted by resin coating compositions presently available or which will become available on the market.

As can be seen in Figures 1, 3 and 4, the body 2 is mounted onto a set of four swivel casters 4, 5, 6 and 7. These casters are advantageously made of or covered with soft rubber material to prevent marking of the coating 90 and of the top surface of the floor 90 as the irradiating apparatus is displaced. The wheeled body can therefore be easily displaced in any direction by an operator standing behind the apparatus 1 through the handles such as 89 (Figure 3). It should be pointed out here that, in operation, the wheeled body 2a is pushed forwardly by the operator through the handles such as 89. The irradiation module 2b accordingly precedes the swivel casters 4 - 7 and the operator. As hardening of the coating 54 is very fast when irradiated with ultraviolet light, the casters 4 - 7 and the operator accordingly roll and walks on a hard surface.

.. . . ~
, '~ "' ~
..

20438~9 The body 2a and the housing 3 are made of a frame (see for example 8 in Figure 3), made of aluminium, and covered with sheet aluminium (see for example 9 and 10 in Figure 3). The use of aluminium obviously reduces the weight of the apparatus 1 to thereby prevent marking of the coating 54 and floor 90 by the swivel casters 4 - 7. This type of construction is well known by those skilled in the art and does not need to be further described in the present description.

The housing 3 can be moved horizontally along a transversal track system. This track system comprises a transversal track 11, made of aluminium.
The track 11 is tubular, has a square cross section and is formed with a longitudinal bottom slot 12. The track 11 is secured to the front face 14 of the wheeled body 2a through a pair of alumimium brackets such as 13, of current design.
The housing 3 comprises a top face 15.
An elongated and transversal aluminium member has a cross section defining a right angle and comprises (a) an horizontal portion 16 fastened to the top face 15 and (b) a vertical portion 17 (Figures 1 and 3) on the two sides of which are rotatably mounted ball bearings such 18 and 19 (Figure 3~. Obviously, ball bearings such as 18 and 19 are distributed along the vertical portion 17.
A transversal square tube 20 is fastened to a pair of lateral U-shaped brackets 21 and 22 each having two ends themselves fastened to the top face 15 :

.. :

20438~9 of the housing 3. Two lateral ball bearings 23 and 24, mounted under the free end of brackets 25 and 26, rotate about respective vertical axes and roll on the front face 27 (Figure 4) of the tube 20, preferably made of aluminium to reduce as much as possible the weight of the apparatus 1. The brackets 25 and 26, of current design and made of aluminium, are connected to the front face 14 of the wheeled body 2a.

Another pair of ball bearings such as 28 roll onto the lower portion of the rear face 29 of the housing 3. Each wheel 28 rotate about a corresponding vertical axis, and is secured to the front face 14 of the wheeled body 2a through respective right angle brackets such as 30.

As best shown in Figure 6, the rear face 29 of the front housing 3 is formed with a transversely extending channel 31. This channel 31 opens through the rear face 29 of the housing 3 through a longitudinal and transversal slot 32.
toothed rack 33 is attached to the bottom of the channel 31.

Referring now to Figures 2 and 3 of the drawings, the channel 31 is dimensioned to receive a pair of lateral toothed wheels 34 and 35 of which the teeth are meshed with the teeth of the rack 33. Each wheel 34,35 is mounted on a shaft 36,37 passing through the slot 32 tFigure 6), the front wall 9 of the body 2a, a reinforcing plate member 38 fixed on the inner face of the front wall 9. Each shaft 36,37 rotates in ball bearings such as 40 secured on the 2~4385~

inner face of the reinforcing plate 38. At the end of the shaft 36,37 opposite to the toothed wheel 34,35 is mounted a gear 41,42. Another gear 43 is mounted on the shaft 36 adjacent the gear 41. The gears ~1 and 42 are interconnected through an endless chain 44, while another endless chain 45 links the gear 43 and another gear 46 mounted on the shaft of a reversible electric motor 47 itself disposed in the body 2a.

In operation, when the motor 47 rotates in a first direction 100 (Figure 2), the rotational movement is transmitted to the toothed wheels 34 and 35 through the gear 46, the chain 45, the gears 41 and 42, the chain 44, and the driving shafts 36 and 37.
As the toothed wheels are meshed with the toothed rack 33, the irradiation module 2b is then moved laterally in the corresponding direction 101 (Figures 2 and 4).
During this lateral movement, the ball bearings 18 and 19 roll into the tubular track 11, the ball bearings 23 and 24 roll on the tube 20, and the two ball bearings such as 28 roll on the rear face 29 of the housing 3. Lateral movement of the irradiation module 2b is of course facilitated by the ball bearings of the track system.
If the direction of rotation of the reversible motor 47 is reversed (see 102 in Figure 2), the rotational movement is transmitted to the toothed wheels 34 and 35 in the same manner, but the irradiation module 2b then moves laterally in the opposite direction 103 (Figures 2 and 4).

2~38~9 When the floor of a closet should be irradiated, the wheeled body 2a is displaced forwardly through the handles such as 89 until the irradiation module 2b is situated into the closet. The motor 47 is then operated to move the module 2b laterally and thereby irradiate the end corner portions of the floor in the closet. Lateral movement of the module 2b accordingly enables easy irradiation of floor portions which would otherwise be difficult of access.
As can be appreciated, the irradiation module 2b can be moved laterally in either direction 101 or 103 until the ball bearings 18 and 19 and the vertical portion 17 disengage the tubular track 11 and the ball bearings 23 and 24 disengage the front face of the square tube 20. The body 2 and housing 3 are then disassembled. The apparatus 1 is accordingly structured to allow easy dismantlement of the irradiation module 2b to facilite the transport.
The irradiation module 2b will now be described in more detail with reference to Figures 5 and 6 of the appended drawings.

This module 2b comprises the front housing 3 which has been introduced in the foregoing description. An elongated and transversal casing 49 is mounted on the inside of the rear wall 48 of the housing 3 through an hinge 50. An elongated spacer 51 is however interposed between the hinge 50 and the rear wall 48 to enable adequate pivoting of the casing 49 on the wall 48, as will be seen in the following description.

.

ll As shown in Figure 6, a well known tubular mercury lamp 52, capable of producing ultraviolet light without generating ozone, and a reflector 52 are fixedly mounted within the casing 49. A lamp 55 capable of generating a luminous power of 200-300 watts by inch is generally adequate. The reflector 52 is parallel to the tubular lamp 52 and is positioned above this lamp. It further presents a downwardly oriented concave surface shaped to reflect the ultraviolet light generated by the lamp 52 toward the floor 90 (Figure 3). This type of reflector is well known in the art and does not need to be further described. Of course, the casing 49 has a bottom opening through which the ultraviolet light from the lamp 52 is projected onto the surface of the floor 90.

A vertical rod 55, passing through the top wall 66 of the housing 3, has a lower end pivotally connected to a bracket 56 itself fastened to the top surface 57 of the casing 49 on the front portion thereof. A handle 58~ mounted on the upper end of the rod 55, can be raised or lowered to pivot manually as desired the casing 49 through the rod 55, as shown in Figure 6 by dashed lines and by the arrows 60 and 105.
When the casing has been pivoted in the desired position, a chuck 59 is tightened on the rod 55; the chuck 59 then rests onto the top surface of the wall 66 to maintain the casing 49 in the adjusted position.
Loosening of the chuck 59 enables subsequent pivoting of the casing 49, when required.

When the portion of floor adjacent a wall or adjacent the inwardly offset base of kitchen 12 20438~9 cabinets, which is difficult to reach, has to be irradiated, a flap 62 formed at the lower end of the vertical front wall 63 of the housing 3 is pivoted upwardly (see 62') by means of an hinge 64. A
permanent magnet 65 fastened to the lower portion of the outer face of the flap 62 can be used to hold the flap in its upper position (see 62'). A piece of mild iron (not shown) can be attached on the outer face of the wall 63 to attract the magnet 65.

When the flap 62 is raised (position 62' in Figure 6) and the casing 49 has been adjusted in the position 49' (Figure 6), ultraviolet light from the lamp 52 and reflector 53 can reach the floor ad~acent a wall or adjacent the inwardly offset base of kitchen cabinets.

In the same manner, the casing 49 can be tilted rearwardly (position 49'' in Figure 6) to allow the lamp 52 to irradiate the floor adjacent a wall close to the rear face 29 of the front housing 3.

Irradiation can be interrupted by means of a shutter 66 that can be operated (arrow 110 in Figure 6) to close the bottom opening of the casing 49. For that purpose, the shutter 66 is hinged at 67 and comprises at one end thereof a triangular bracket 68. A vertical rod 69 passes through the top wall 66 of the housing 3. It comprises a lower end pivotally connected to the free corner of the triangular bracket 68, and an upper end provided with a handle 70. As can be appreciated, the shutter 66 can be operated through the handle 70 by moving longitudinally the rod 20438~9 69 (see arrows 71). When the desired position for the shutter 66 is reached, a chuck 72 is tightened on the rod 69 and rests on the top face of the wall 66 to hold the shutter 66 in this desired position.
Loosening of the chuck 72 ena~les subsequent operation of the shutter 66.

A blower 73 is mounted within the wheeled body 2a in order to cool the interior of the casing 79. The blower 73 sucks air through the inlet 74 (Figures 1, 4 and 5) formed in the front wall 63 of the housing 3, a flexible conduit 75 (Figure 5) interconnecting the inlet 74 and the interior of the casing 49, the interior of the elongated casing 49, and flexible conduits 76 and 77 and a rigid conduit 78 interconnecting the interior of the casing 49 at the end of this casing opposite the conduit 75 and the blower 73. The so sucked air is evacuated to the outside through an outlet 80 (Figure 1) and another flexible conduit 79 interconnecting the blower 73 and the air outlet 80. The blower 73 is driven by means of an electric motor 81 (Figure 3).

The flow of air generated by the blower 73 in the casing 49 obviously cools the lamp 52 and generally the interior of this casing.

Additional air inlet 81 and 82 located in the front wall 9 aerate the interior of the body 2a.
The lower end of the flexible conduit 77 is secured by means of a collar 83 whereby it can be 20g38S9 easily detached to enable complete separation of the irradiation module 2b from the wheeled body 2a. The electric wires 84 supplying the lamp 52 can also be withdrawn from the body 2a by means of separable connectors 85 and 86 to completely dismantle the irradiation module 2b from the body 2a.

The wheeled body 2a further comprises a vertical, telescopic pole member 87 provided at its upper end with an S-shaped hook 88 to support supply wires (not shown) connectable to an A.C. outlet (not shown). Also, another support member 111 is mounted on the housing 3 to support the wires 84.

The electric circuit supplying the lamp 52 and the motors 47 and 81, and controlling the operation thereof is beleived to be within the skill of an expert in the art and accordingly will not be further described.
The apparatus in accordance with the present invention presents, in particular but not exclusively, the following advantages:

- The body 2a is supported by a set of four swivel casters 4 - 7 whereby it can be easily displaced manually on the floor 90 in any direction through the handles such as 89;

- The irradiation module 2b can be displaced laterally with respect to the wheeled body 2a whereby the ultraviolet light-curable liquid , 20438~9 coating applied on portions of floor of which the access is difficult can be easily irradiated; and - The casing 49 can be tilted and the flap 62 raised to irradiate floor portions close to a wall or to the inwardly offset base of kitchen cabinets, which floor portions would otherwise be difficult to reach.

Although the present invention has been described hereinabove by way of a preferred embodiment thereof, this embodiment can be modified at will, within the scope of the appended claims, without departing from the spirit and nature of the subject invention. For example, the wheeled body 2a can be motorized to be displaced at constant speed suitable to adequately cure and harden the coating.

Claims (18)

1. An apparatus for irradiating a light-curable liquid coating applied on a floor, comprising:
a wheeled body displaceable onto the floor; and an irradiation module for generating light which is projected onto said floor to thereby irradiate the light-curable liquid coating, said generated light being capable of curing said coating;
wherein the irradiation module is mounted on the wheeled body through a mechanism capable of moving said module with respect to said body in order to irradiate the light-curable coating applied on portions of said floor difficult to reach.
2. The apparatus of claim 1, wherein said coating is an ultraviolet light-curable liquid coating and wherein said generated light comprises ultraviolet light.
3. The apparatus of claim 1, wherein the irradiation module comprises:
a light-generating lamp;
a reflector for reflecting light generated by said lamp toward the floor; and another mechanism for tilting said reflector in order to reflect light generated by said lamp on the coating applied on portions of said floor of which the access is difficult.
4. The apparatus of claim 3, in which said irradiation module comprises a housing in which said lamp and said reflector are disposed, said housing comprising a vertical wall provided with a lower flap that can be pivoted to enable, when the reflector is tilted, the light generated by the lamp to irradiate the portions of floor of which the access is difficult.
5. The apparatus of claim 3, in which the irradiation module further comprises a casing containing said lamp and said reflector and having a bottom opening through which the light generated by said lamp irradiates said coating applied on the floor.
6. The apparatus of claim 5, in which the tilting mechanism comprises means for tilting the said casing containing the lamp and the reflector.
7. The apparatus of claim 6, wherein said irradiation module comprises a housing in which said casing containing the lamp and the reflector is disposed, said housing including a vertical wall provided with a lower flap that can be pivoted to enable, when the casing is tilted, the light generated by said lamp to irradiate the portions of floor of which the access is difficult.
8. The apparatus of claim 5, wherein said casing containing the lamp and the reflector comprises a shutter operable to close said bottom opening in order to interrupt irradiation of the light-curable coating.
9. The apparatus of claim 5, further comprising a system for ventilating the interior of said casing.
10. The apparatus of claim 1, wherein the wheeled body comprises a plurality of swivel casters.
11. The apparatus of claim 1, in which said mechanism comprises means for moving the irradiation module horizontally with respect to the wheeled body.
12. The apparatus of claim 1, wherein said mechanism comprises a track system mounted on the wheeled body, supporting the irradiation module, and along which said module moves.
13. The apparatus of claim 12, wherein said mechanism further comprises an elongated toothed rack fixedly mounted on the irradiation module, said rack extending generally parallel to the track system.
14. The apparatus of claim 13, in which the mechanism further comprises a toothed wheel meshed with said toothed rack and mounted on a driving shaft rotatable by an electric motor disposed on the wheeled body, whereby rotation of the driving shaft by said motor rotates the toothed wheel meshed with said rack to move the irradiation module along the track system.
15. The apparatus of claim 14, wherein said electric motor is reversible to move the irradiation module along the track system in two opposite directions.
16. The apparatus of claim 1, in which said mechanism comprises means for moving the said irradiation module transversely in either direction.
17. The apparatus of claim 1, wherein said mechanism comprises means for dismantling the irradiation module from the wheeled body.
18. The apparatus of claim 12, wherein said mechanism comprises means for moving the irradiation module along the track system until it disengages said track system and it is dismantled from the wheeled body.
CA 2043859 1991-06-04 1991-06-04 Apparatus for irradiating an ultraviolet light-curable liquid coating applied on a floor Abandoned CA2043859A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CA 2043859 CA2043859A1 (en) 1991-06-04 1991-06-04 Apparatus for irradiating an ultraviolet light-curable liquid coating applied on a floor

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CA 2043859 CA2043859A1 (en) 1991-06-04 1991-06-04 Apparatus for irradiating an ultraviolet light-curable liquid coating applied on a floor

Publications (1)

Publication Number Publication Date
CA2043859A1 true CA2043859A1 (en) 1992-12-05

Family

ID=4147734

Family Applications (1)

Application Number Title Priority Date Filing Date
CA 2043859 Abandoned CA2043859A1 (en) 1991-06-04 1991-06-04 Apparatus for irradiating an ultraviolet light-curable liquid coating applied on a floor

Country Status (1)

Country Link
CA (1) CA2043859A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1140364A1 (en) * 1999-09-17 2001-10-10 Minuteman International, Inc. Apparatus for curing floor coating

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1140364A1 (en) * 1999-09-17 2001-10-10 Minuteman International, Inc. Apparatus for curing floor coating
EP1140364A4 (en) * 1999-09-17 2005-02-02 Minuteman International Inc Apparatus for curing floor coating

Similar Documents

Publication Publication Date Title
US3945449A (en) Wheeled attachment for a chair
US9188388B2 (en) Portable ultraviolet floor curing device
US4503925A (en) Detachable steerable power unit for occupant-propelled wheelchairs
US7004284B2 (en) Scaffold moving device
US3921740A (en) Self-propelled vehicle
US6375209B1 (en) Powered wheelchair
JP5371019B2 (en) Lifting vehicle
CA2342845C (en) Wheelchair with aerobic attachment
CN105031679B (en) Portable UV disinfection units and its method for place
US5390753A (en) Personal walker with powered wheels
CA2411296C (en) Vacuum nozzle apparatus
US20080271948A1 (en) Motorized climbing hunting stand
US2620041A (en) Endless tread stair climbing truck
US5413187A (en) Personal mobility vehicle
JPH04302664A (en) Floor cover removing device
WO2001094167A1 (en) Repair device for vehicle
US2675660A (en) Disk type mower
US5867926A (en) Hot air snow and ice remover
CA2043859A1 (en) Apparatus for irradiating an ultraviolet light-curable liquid coating applied on a floor
US20080229530A1 (en) Grout cleaning apparatus
US20100242298A1 (en) Ultraviolet curing system including supplemental energy source
US20070235234A1 (en) Wheelchair and Carrying Wheel Provided with a Wheel Motor for Use in Such a Wheelchair
US2559495A (en) Portable air controller
US8890098B2 (en) Ultraviolet floor curing device employing offset wheel arrangement
US3282363A (en) Tractor means for extending and retracting bleacher stand sections

Legal Events

Date Code Title Description
FZDE Dead